Therapy adjustment based on patient event indication

ABSTRACT

An indication that a patient event occurred may be used to evaluate the efficacy of at least one therapy program and/or adjust therapy delivery to the patient. In some examples, the patient event indication includes patient input that may be received via an event indication button of a programming device. In some examples, therapy delivery may be adjusted by adjusting at least one therapy parameter value, switching therapy programs or therapy program groups or restarting a therapy cycle of a medical device.

This application is a continuation of U.S. patent application Ser. No.12/236,260, entitled, “THERAPY ADJUSTMENT BASED ON PATIENT EVENTINDICATION” and filed on Sep. 23, 2008, which claims the benefit of U.S.Provisional No. 60/974,691 to Giftakis et al., entitled, “PATIENT EVENTINDICATION” and filed on Sep. 24, 2007 and U.S. Provisional No.60/974,726 to Kovach et al., entitled, “PATIENT EVENT INFORMATION” andfiled on Sep. 24, 2007. The entire contents of above-identified U.S.patent application Ser. No. 12/236,260 and U.S. Provisional ApplicationNos. 60/974,691 and 60/974,726 are incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to therapy systems, and more particularly,control and evaluation of therapy systems.

BACKGROUND

Medical devices may be used to deliver therapy to patients to treat avariety of symptoms or conditions, such as epilepsy, chronic pain,tremor, Parkinson's disease, psychiatric disorders, neuralgia, urinaryor fecal incontinence, sexual dysfunction, obesity, or gastroparesis. Amedical device may deliver stimulation therapy via leads that includeelectrodes located proximate to the spinal cord, pelvic nerves, stomach,or within the brain of a patient. The stimulation site may be selectedon the particular patient condition being managed by the stimulationsystem. In some cases, at least some electrodes may be integrated withan implantable pulse generator.

In another type of therapy, a medical device may deliver a drug oranother fluid to a specific tissue site within the patient via acatheter attached to the medical device. In any case, the medical deviceis used to provide treatment to the patient as needed in order inincrease the quality of life of the patient. The medical device may beimplanted or located externally, depending upon the type of therapy andneeds of the patient.

A clinician may program the medical device to effectively treat thepatient. For example, the clinician may define the therapy to bedelivered to a patient by selecting values for one or more programmabletherapy parameters. The therapy parameters may define a therapy program,and in some cases, a medical device delivers therapy in accordance withmore than one program, which may be arranged in a program group. As oneexample, in the case of electrical stimulation, the clinician may selectan amplitude, which may be a current or voltage amplitude, a pulse widthfor a stimulation waveform to be delivered to the patient, as well as arate at which the pulses are to be delivered to the patient.Programmable therapy parameters also may include electrode combinationsand polarities. The clinician may also create multiple programs havingvarious different therapy parameter combinations that the patient mayuse as desired in order to find the most effective therapy parameters totreat a condition.

SUMMARY

In general, the disclosure is directed to evaluating one or more therapyprograms or groups of programs or adjusting therapy delivered by amedical device based on an indication that a patient event occurred. Theevent may be, for example, the occurrence of a symptom related to thepatient's condition, such as an aura related to a seizure or a headacherelated to migraines. In some examples, the indication that a patientevent occurred is received via patient input. In addition to or insteadof the patient input, the indication that a patient event occurred maybe received from a sensor that detects the occurrence of the patientevent based on one or more physiological parameter values of thepatient. In some examples, the indication that the patient eventoccurred may be automatically generated based on at least one monitoredphysiological parameter value of the patient.

In some examples, one or more therapy programs or groups may beevaluated based on the patient event indications. In addition, inexamples, the patient event indication may be used to adjust therapy,such as restarting a therapy cycle or modifying a duration of a therapycycle. In some examples, activation of the event indication button orother receipt of a patient event indication may trigger the medicaldevice or a sensing device to begin recording physiological parametervalues of the patient, such as electroencephalogram (EEG) signals,electrocardiogram (ECG) signals, respiratory signals, blood pressure orbody temperature. The physiological parameter values may be useful to,for example, diagnose the patient's condition or formulate a bettertherapy plan.

In some examples, the clinician may evaluate whether a patientprogrammer that includes an event indication button that allows apatient some control over therapy delivery is a useful feature. Thepatient programmer may be evaluated during a trial stage. The clinicianmay determine whether to implement the patient programmer including afunctional event indication button based on the patient's frequency ofusage of the event indication button and feedback indicating theefficacy of the event indication button during the trial stage.

In one aspect, the disclosure is directed to a method comprisingreceiving input from a patient indicating an occurrence of a patientevent related to a condition of the patient, generating an event markerbased on the input from the patient, and adjusting therapy delivered bya medical device to the patient. The medical device delivers therapyaccording to a therapy cycle comprising an on-cycle and an off-cycle,and adjusting therapy comprises determining whether the medical deviceis in the off-cycle or the on-cycle at a time the event marker isgenerated, initiating the on-cycle if the medical device is in theoff-cycle at the time the event marker is generated, and restarting theon-cycle if the medical device is in the on-cycle at the time the eventmarker is generated.

In another aspect, the disclosure is directed to a system comprising amedical device that delivers therapy to a patient according to a therapycycle comprising an on-cycle and an off-cycle, and a processor thatreceives input from a patient indicating an occurrence of a patientevent, where the patient event is related to a condition of the patient,generates an event marker based on the input, determines whether themedical device is in the off-cycle or the on-cycle at a time the eventmarker is generated, initiates the on-cycle if the medical device is inthe off-cycle at the time the event marker is generated, and restartsthe on-cycle if the medical device is in the on-cycle at the time theevent marker is generated.

In another aspect, the disclosure is directed to a system comprisingmeans for receiving input from a patient indicating an occurrence of apatient event related to a condition of the patient, means forgenerating an event marker based on the input from the patient, andmeans for adjusting therapy delivered by a medical device to thepatient, where the medical device delivers therapy according to atherapy cycle comprising an on-cycle and an off-cycle. The means foradjusting therapy comprises means for determining whether the medicaldevice is in the off-cycle or the on-cycle at a time the event marker isgenerated, means for initiating the on-cycle if the medical device is inthe off-cycle at the time the event marker is generated, and means forrestarting the on-cycle if the medical device is in the on-cycle at thetime the event marker is generated.

In another aspect, the disclosure is directed to a computer-readablemedium comprising instructions. The instructions cause a programmableprocessor to receive input from a patient indicating an occurrence of apatient event, wherein the patient event is related to a condition ofthe patient, generate an event marker based on the input from thepatient, and adjust therapy delivered by a medical device to thepatient. The medical device delivers therapy according to a therapycycle comprising an on-cycle and an off-cycle, and the instructionscause the programmable processor to determine whether the medical deviceis in the off-cycle or the on-cycle at a time the event marker isgenerated, initiate the on-cycle if the medical device is in theoff-cycle at the time the event marker is generated, and restart theon-cycle if the medical device is in the on-cycle at the time the eventmarker is generated.

In another aspect, the disclosure is directed to a computer-readablemedium comprising instructions. The instructions cause a programmableprocessor to perform any of the techniques described herein.

The details of one or more examples of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the disclosure will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram illustrating an example therapy systemincluding an implantable medical device, a patient programmer, and aclinician programmer.

FIG. 2 is a schematic block diagram illustrating components of theimplantable medical device of FIG. 1.

FIG. 3 is a schematic block diagram illustrating components of thepatient programmer of FIG. 1.

FIG. 4 is a schematic block diagram illustrating components of theclinician programmer of FIG. 1.

FIG. 5 is a schematic plan view of an example patient programmer thatincludes an event indication button.

FIGS. 6A and 6B are flow diagrams illustrating example techniques thatinclude switching between therapy program groups based on receiving anindication of a patient event.

FIG. 7 is a flow diagram illustrating an example technique for adjustingtherapy delivery to patient 14 based on patient event indications.

FIG. 8 is a flow diagram illustrating an example technique that includesevaluating the efficacy of one or more therapy programs based onindications of a patient event.

FIG. 9 is a flow diagram illustrating an example technique that includesadjusting therapy delivery based on receiving an indication of a patientevent.

FIG. 10 is a flow diagram illustrating another example technique thatincludes adjusting therapy delivery based on receiving an indication ofa patient event.

FIGS. 11A-11D are timing diagrams illustrating different scenarios forrestarting a therapy cycle based on receiving an indication of a patientevent.

FIGS. 12A and 12B are flow diagrams illustrating example techniques forconfirming patient input indicating an occurrence of a patient event.

FIG. 13 is a flow diagram illustrating another example technique foradjusting therapy delivery to a patient based on patient eventindications.

FIG. 14 is a flow diagram illustrating an example technique thatincludes delivering a placebo indication to a patient based on receivingan indication of a patient event.

FIG. 15 is a flow diagram illustrating an example technique thatincludes recording patient event information.

FIG. 16 is a flow diagram illustrating an example technique thatincludes obtaining and presenting event information to a user.

FIGS. 17A-17E illustrate example user interfaces that may be presentedby a patient programmer.

DETAILED DESCRIPTION

One or more therapy programs or groups of programs may be evaluated ortherapy parameters may be adjusted based on an indication that a patientevent occurred. Systems described herein are configured to receive anindication of a patient event. The patient event may include, forexample, the occurrence of a symptom of a patient's condition, such asan aura related to a seizure or a headache related to migraines. In someexamples, the indication of the event may be received via an eventindication button of a computing device, such as a patient programmer.For example, an external programmer may include an event indicationbutton. The button is not limited to depressible buttons, but may alsobe presented as a selectable portion of a touch screen, a knob, or anyother suitable mechanisms or media of receiving patient input. Forconvenience, any such media may be generally referred to herein as abutton.

In other examples, patient input indicating an occurrence of a patientevent may be received via other techniques. For example, the patient mayprovide input indicating the occurrence of a patient event by tappingthe skin located proximate to an implanted medical device, as describedin commonly-assigned U.S. patent application Ser. No. 11/755,559 toGerber et al., which is entitled, “AUTOMATIC VOIDING DIARY,” and wasfiled on May 30, 2007. U.S. patent application Ser. No. 11/755,559 toGerber et al. is incorporated herein by reference in its entirety.Although U.S. patent application Ser. No. 11/755,559 describes tapping amedical device to provide input indicating the occurrence of a voidingevent, the tapping of the medical device may be applicable to thepresent disclosure to provide patient input indicating the occurrence ofany suitable patient event, which may or may not include a voidingevent.

An implanted medical device may include an input mechanism thatgenerates an electrical signal based on one or more characteristics ofthe tapping, e.g., the number, frequency, and duration. The inputmechanism that generates the electrical signal based on the tapping ofthe medical device may include, for example, a multiple or single axisaccelerometer or a strain gauge that produces a detectable change inelectrical resistance based on the extent of deformation of the straingauge, although other input mechanisms may be possible. Tapping thepatient's skin near the implanted medical device may cause the patient'sepidermis and subcutaneous tissue to compress and/or deflect in thedirection of motion of tapping, which may cause the medical device to bedisplaced from original location for a period of time before returningto original location. A processor of the medical device or anotherdevice, such as an external programmer, may process the accelerometersignal or strain gage signal and identify the patient input based on thecharacteristics of the electrical signal.

Instead of in addition to the patient input, in other examples, thepatient event indication may be generated based on at least onemonitored physiological parameter value of the patient, such as, but notlimited to, an electroencephalogram (EEG) signal, electrocardiogram(ECG) signal, respiratory signals, blood pressure or body temperature. Amedical device may monitor the at least one physiological parametervalue of the patient and determine whether the patient event occurredbased on the at least one physiological parameter value.

An event marker may be generated upon receipt of the indication that thepatient event occurred. A computing device, such as a patientprogrammer, clinician programmer or a medical device, may generate a logof the event markers, which generally reflects the time and date thepatient felt a symptom of the patient's condition, based on actuation ofthe event indication button. In this way, the stored event markers mayprovide a log of patient event occurrences. In some examples, the eventmarker may also reflect the duration of the patient event. For example,a patient may provide input indicating the occurrence of the patientevent and also provide input upon cessation of the patient event, and acomputing device may automatically determine the duration of the patientevent. In other examples, the patient may provide input indicating theduration of the patient event and the computing device may associate thepatient-provided duration with the event marker in a memory of a device.

In some examples, one or more therapy programs or groups may beevaluated based on the patient event indications. For example, acomputing device may associate the event marker with a therapy programor program group in order to evaluate the efficacy of the therapyprogram or group of therapy programs. In other examples, a clinician maymanually associate the event markers with a particular therapy programor group. The number of event markers associated with the therapyprogram or group may be indicative of the efficacy of the respectiveprogram or group.

The computing device may calculate an event metric for a therapy programor group based on the one or more associated event markers, and comparethe event metric to a threshold value in order to determine whether therespective program or group provides efficacious therapy to the patient.In some examples, the event metric may include a total number of eventmarkers associated with the program or group, a number of event markersper unit of time associated with the program or group, a change from abaseline condition of the patient during the time the medical devicedelivered therapy according to the respective program or group, or ascore that indicates the type or severity of the patient events thathave occurred.

In some examples, the patient event indication may be used to adjusttherapy. For example, a computing device may control a medical device torestart a therapy cycle or otherwise modify therapy (e.g., changeanother therapy parameter) in response to receiving the event marker. Atherapy cycle may include at least one on-cycle in which therapy isdelivered and at least one off-cycle in which therapy is not delivered.The therapy cycle may depend on the patient's condition, as well as thetarget stimulation site within the patient. The logging of eventmarkers, evaluating efficacy of therapy programs or program groups,and/or controlling a medical device in response to receiving anindication of the occurrence of an event may be used in combination witheach other, if desired. In one example, a programming device receivesthe indication of the patient event via an event indication button, andcontrols a medical device to restart a therapy cycle. In this way, thepatient may directly affect therapy delivery by providing input via theevent indication button of a programming device.

If the medical device is configured to operate in a substantiallyopen-loop, such that the medical device delivers therapy to the patientin a substantially continuous cycle, activation of the event indicationbutton may modify the open loop. For example, if the event indicationbutton is activated during an off-cycle portion of the therapy cycle,the duration of the current therapy cycle may be shortened as comparedto a normal therapy cycle. The “normal” therapy cycle may include atleast one on-cycle in which therapy is delivered and at least oneoff-cycle in which therapy is not delivered. If the event indicationbutton is received during an on-cycle, a programming device may providea signal to a medical device to restart the therapy cycle. As a result,the duration of the therapy cycle may increase because the duration ofthe on-cycle increases. However, regardless of the shortened orelongated therapy cycles, subsequent therapy cycles may return to thenormal therapy cycle length.

In some examples, activation of the event indication button or otherreceipt of a patient event indication may trigger the medical device ora sensing device to begin recording physiological parameter values ofthe patient, such as electroencephalogram (EEG) signals,electrocardiogram (ECG) signals, respiratory signals, blood pressure orbody temperature. A clinician may later retrieve the recordedphysiological parameter values in order to evaluate the patient'scondition at the time the patient event occurred (e.g., at the time thepatient event button was activated). The physiological parameter valuesmay be useful to, for example, diagnose the patient's condition orformulate a better therapy plan. Activation of the event indicationbutton may also trigger another device, such as a video recorder tovideotape the patient, which a clinician may later review to, amongother things, diagnose the patient based on visible changes to thepatient after the event indication button was triggered.

In some examples, the clinician may evaluate whether a patientprogrammer that includes an event indication button that allows apatient some control over therapy delivery is a useful feature. Thepatient programmer may be evaluated during a trial stage. The clinicianmay determine whether to implement the patient programmer including afunctional event indication button based on the patient's frequency ofusage of the event indication button and feedback indicating theefficacy of the event indication button during the trial stage.

The systems and methods described herein primarily refer examples inwhich the patient event is a seizure. However, in other examples, thesystems and methods described herein are useful with other patientevents, such as, but not limited to, headaches or other afflictions ofpain, psychiatric disorders, such as anxiety disorders (e.g., panic oranxiety attacks), depressive episodes, manic episodes, and movementdisorder episodes, such as a tremor episode.

Seizure disorders are characterized by the occurrence of seizures. Forexample, epilepsy is a neurological disorder characterized by theoccurrence of seizures, although seizures may also occur in persons whodo not have epilepsy. Seizures are typically attributable to abnormalelectrical activity of a group of brain cells. A seizure may occur whenthe electrical activity of certain regions of the brain, or even theentire brain, becomes abnormally synchronized. The onset of a seizuremay be debilitating. For example, the onset of a seizure may result ininvoluntary changes in body movement, body function, sensation,awareness or behavior (e.g., an altered mental state). In some cases,each seizure may cause some damage to the brain, which may result inprogressive loss of brain function over time.

Therapy delivery systems may be used to treat seizures to mitigate theeffects of many patient conditions or disorders. Electrical stimulationtherapy or delivery of a fluid (e.g., a drug or another pharmaceuticalagent) to the patient may shorten the duration of the seizure, preventthe onset of seizures or minimize the severity of the seizure. In somecases, the electrical stimulation is provided to one or more regions ofthe brain at regular intervals, substantially continuously or upon thedetection or prediction of some event, such as the detection of aseizure by EEG sensors implanted within the brain, or at the directionof the patient or clinician. In the case of drug deliver therapy, drugsmay be orally introduced into the patient or infused directly into ablood stream or one or more regions of the brain of the patient atregular intervals, substantially continuously or upon the detection orprediction of some event, such as the detection of a seizure by EEGsensors implanted within the brain, or at the direction of the patientor clinician.

In open loop therapy systems, therapy is delivered substantiallycontinuously or at regular intervals for an indefinite period of timewithout relying on feedback from the system. In contrast, closed loop orresponsive therapy systems deliver therapy in response to the detectionor prediction of some event, which may be detected or predicted bymonitoring one or more physiological parameters of the patient. In thecase of seizures, for example, the closed-loop or responsive therapysystem may deliver therapy in response to the detection of a seizure byEEG sensors within the patient's brain or motion detectors that detectthe physical symptoms of a seizure. In a closed loop therapy system, themedical device may continue delivering therapy until it determines theseizure has ceased.

FIG. 1 is a conceptual diagram illustrating an example of an open-looptherapy system 10 that is implanted proximate to brain 12 of patient 14in order to help manage the patient's seizures. While patient 14 isgenerally referred to as a human patient, other mammalian ornon-mammalian patients are also contemplated. In the example shown inFIG. 1, therapy system 10 is a brain stimulation system (DBS) becausetherapy system 10 provides therapy directly to tissue within brain 12.Therapy system 10 includes implantable medical device (IMD) 16, leadextension 18, leads 20A and 20B, clinician programmer 22, and patientprogrammer 24. IMD 16 includes a therapy module that delivers electricalstimulation therapy to one or more regions of brain 12 via leads 20A and20B at regular intervals.

In some examples, stimulation sessions (“on-cycles”) are separated bysessions in which no stimulation is delivered (“off-cycles”). During an“on-cycle,” stimulation may be turned on and off, for example, ifstimulation is provided as pulses or bursts of pulses. Together, theon-cycle and off-cycle define a therapy cycle, which may include morethan one on-cycle and/or more than one off-cycle. As one example of atherapy cycle, IMD 16 may deliver stimulation in five minute intervals,where stimulation is delivered for about one minute. That is, theon-cycle is about one minute and the off-cycle is about five minutes.However, other therapy cycles are also contemplated. The therapy cyclemay depend upon the patient's condition, such as the type of seizuresexperienced by patient 14, the duration of the seizures or the severityof the seizures.

In the example shown in FIG. 1, IMD 16 is implanted within a chestcavity of patient 14. In other examples, IMD 16 may be implanted withinother regions of patient 14, such as a subcutaneous pocket in theabdomen of patient 14 or the cranium of patient 14. Implanted leadextension 18 is coupled to IMD 16 via connector block 26, which mayinclude, for example, electrical contacts that electrically couple torespective electrical contacts on lead extension 18. The electricalcontacts electrically couple the electrodes carried by leads 20A and 20B (collectively “leads 20”) to IMD 18. Lead extension 18 traverses fromthe implant site of IMD 16 within a chest cavity of patient 14, andalong the neck of patient 14 to the cranium of patient 14 to accessbrain 12. Leads 20 are implanted within the right and left hemispheres,respectively, of brain 12 in order deliver electrical stimulation to oneor more regions of brain 12, which may be selected based on manyfactors, such as the type of seizures afflicting patient 14.Neurological disorders that cause seizures, such as epilepsy, may begenerated in one or more of regions of the brain, which may differbetween patients.

Although leads 20 are shown in FIG. 1 as being coupled to a common leadextension 18, in other examples, leads 20 may be coupled to IMD 16 viaseparate lead extensions or directly coupled to IMD 16. Leads 20 maydeliver electrical stimulation to treat any number of neurologicaldisorders or diseases in addition to seizures, such as movementdisorders and psychiatric disorders. Examples of movement disordersinclude a reduction in muscle control, motion impairment or othermovement problems, such as rigidity, bradykinesia, rhythmichyperkinesia, nonrhythmic hyperkinesia, and akinesia. Psychiatricdisorders include major depressive disorder (MDD), bipolar disorder,anxiety disorders, post traumatic stress disorder, dysthymic disorder,and obsessive-compulsive disorder (OCD).

Leads 20 may be implanted within a desired location of brain 12 via anysuitable technique, such as through respective burr holes in a skull ofpatient 14 or through a common burr hole in the cranium. Leads 20 may beplaced at any location within brain 12 such that the electrodes of theleads are capable of providing electrical stimulation to targeted tissueduring treatment. Electrical stimulation generated from the signalgenerator (not shown) within the therapy module of IMD 16 may helpprevent the onset of seizures or minimize the severity of seizures. Theexact parameter values of the stimulation therapy, such as the amplitudeor magnitude of the stimulation signals, the duration of each stimulus,the waveform of the stimuli (e.g., rectangular, sinusoidal or rampedsignals), may be specific for the particular target stimulation site(e.g., the region of the brain) involved as well as the particularpatient.

In the case of stimulation pulses, the stimulation therapy may becharacterized by selected pulse parameters, such as puke amplitude,pulse rate, and pulse width. In addition, if different electrodes areavailable for delivery of stimulation, the therapy may be furthercharacterized by different electrode combinations, i.e., the electrodesof leads 20 that are selected to deliver therapy to patient 14 and thepolarity of the selected electrodes. Known techniques for determiningthe optimal stimulation parameter value may be employed. In one example,electrodes of leads 20 are positioned to deliver stimulation therapy toan anterior nucleus of the thalamus of brain 12 of patient 14, andstimulation therapy is delivered via a select combination of theelectrodes to the anterior nucleus of the thalamus with electricalstimulation including a frequency of 145 hertz (HZ), a voltage of about4 volts to about 5 volts, and a pulse width of about 90 microseconds.However, other examples may implement stimulation therapy includingother stimulation parameter values.

Other stimulation targets for epilepsy may include, but are not limitedto, the caudate nucleus, locus coeruleus, cerebellum, subthalamicnucleus, cingulate, substantia nigra, and thalamic structures such asthe centromedian nucleus, centrolateral nucleus, and dorsomedial nucleusof brain 12. Stimulation may also be directed in a brain lobe, such asthe frontal, temporal, parietal and occipital lobes. In some examples,if patient 12 suffers frontal lobe seizures, stimulation electrodes ofleads 20 may be positioned directly in the premotor cortex, the motorcortex, and in neural pathways connecting them. In other examples, ifpatient 12 suffers from seizures that originate in medial temporal lobe(MTL) structures, stimulation may be directed at the hippocampus,amygdala, or in both of these structures. For focal seizures, thestimulation lead may be placed at the site of seizure origin, at or nearthe seizure focus, as identified with seizure onset localizationtechniques, including EEG monitoring and brain imaging.

Different neurological or psychiatric disorders may be associated withactivity in one or more of regions of brain 12, which may differ betweenpatients. For example, in the case of MDD, bipolar disorder or OCD,leads 20 may be implanted to deliver electrical stimulation to theanterior limb of the internal capsule of brain 12, and only the ventralportion of the anterior limb of the internal capsule (also referred toas a VC/VS), the subgenual component of the cingulate cortex, anteriorcingulate cortex Brodmann area 32 and 24, various parts of theprefrontal cortex, including the dorsal lateral and medial pre-frontalcortex (PFC) (e.g., Brodmann area 9), ventromedial prefrontal cortex(e.g., Brodmann area 10), the lateral and medial orbitofrontal cortex(e.g., Brodmann area 11), the medial or nucleus accumbens, thalamus,intralaminar thalamic nuclei, amygdala, hippocampus, the lateralhypothalamus, the Locus ceruleus, the dorsal raphe nucleus, ventraltegmentum, the substantia nigra, subthalamic nucleus, the inferiorthalamic peduncle, the dorsal medial nucleus of the thalamus, or anycombination thereof. However, other examples may implement stimulationtherapy including other stimulation parameter values.

In the example shown in FIG. 1, the electrodes of leads 20 comprise ringelectrodes. Ring electrodes may be relatively easy to program and aretypically capable of delivering an electrical field to any tissueadjacent to leads 20. In other examples, the electrodes of leads 20 mayhave different configurations. For examples, the electrodes of leads 20may have a complex electrode array geometry that is capable of producingshaped electrical fields. The complex electrode array geometry mayinclude multiple electrodes (e.g., partial ring or segmented electrodes)around the perimeter of each lead 20, rather than one ring electrode. Inthis manner, electrical stimulation may be directed to a specificdirection from leads 20 to enhance therapy efficacy and reduce possibleadverse side effects from stimulating a large volume of tissue. In someexamples, a housing of IMD 16 may include one or more stimulation and/orsensing electrodes. In alternative examples, leads 20 may have shapesother than elongated cylinders as shown in FIG. 1. For example, leads 20may be paddle leads, spherical leads, bendable leads, or any other typeof shape effective in treating patient 14.

In some examples, leads 20 may include sensing electrodes positioned todetect an EEG signal within one or more region of patient's brain 12.Alternatively, another set of sensing electrodes may monitor the EEGsignal. In some cases, EEG signals from within brain 12 may indicate theoccurrence of seizure. Electrodes implanted closer to the target regionof brain 12 may help generate an EEG signal that provides more usefulinformation than an EEG generated via a surface electrode array becauseof the proximity to brain 12. The EEG signal that is generated fromimplanted electrode array may also be referred to as anelectrocorticography (ECoG).

As described in further detail with reference to FIG. 1, IMD 16 includesa therapy module that generates the electrical stimulation delivered topatient 14 via leads 20. A signal generator (not shown), within IMD 16produces the stimulation in the manner defined by the therapy program orgroup of programs selected by the clinician and/or patient 14. Generallythe signal generator is configured to produce electrical pulses to treatpatient 14. However, the signal generator of IMD 16 may be configured togenerate a continuous wave signal, e.g., a sine wave or triangle wave.In either case, IMD 16 generates the electrical stimulation therapy forDBS according to therapy parameters selected at that given time intherapy.

In the example shown in FIG. 1, IMD 16 generates the electricalstimulation according to one or more therapy parameter values, which maybe arranged in a therapy program (or a parameter set). The therapyprogram includes values for a number of parameters that define thestimulation. For example, the therapy parameters may include voltage orcurrent pulse amplitudes, pulse widths, pulse rates, pulse frequencies,electrode combinations, and the like. IMD 16 may store a plurality ofprograms. In some cases, the one or more stimulation parameters areorganized into groups, and IMD 16 may deliver stimulation to patient 14according to a program group. The stimulation signals according to thedifferent program groups may be delivered on a time-interleaved basis orsubstantially simultaneously. During a trial stage in which IMD 16 isevaluated to determine whether IMD 16 provides efficacious therapy topatient 14, the stored programs may be tested and evaluated forefficacy.

IMD 16 may include a memory to store one or more therapy program (e.g.,arranged in groups), instructions defining the extent to which patient14 may adjust therapy parameters, switch between programs, or undertakeother therapy adjustments. Patient 14 may generate additional programsfor use by IMD 16 via patient programmer 24 at any time during therapyor as designated by the clinician.

Generally, an outer housing of IMD 16 is constructed of a biocompatiblematerial that resists corrosion and degradation from bodily fluids. IMD16 may be implanted within a subcutaneous pocket close to thestimulation site. Although IMD 16 is implanted within a chest cavity ofpatient 14 in the example shown in FIG. 1, in other examples, IMD 16 maybe implanted within cranium or another location within patient 14. Inaddition, while IMD 16 is shown as implanted within patient 14 in FIG.1, in other examples, IMD 16 may be located external to the patient. Forexample, IMD 16 may be a trial stimulator electrically coupled to leads20 via a percutaneous lead during a trial period. If the trialstimulator indicates therapy system 10 provides effective treatment topatient 14, the clinician may implant a chronic stimulator withinpatient 14 for long term treatment.

Clinician programmer 22 may be a handheld computing device that permitsa clinician to program electrical stimulation therapy for patient 14,e.g., using input keys and a display. For example, using clinicianprogrammer 22, the clinician may specify therapy programs that includeone or more therapy parameters and/or organize the therapy programs intotherapy program groups for use in delivery of DBS. Clinician programmer22 supports telemetry (e.g., radio frequency (RF) telemetry) with IMD 16to download stimulation parameter values and/or therapy algorithms(e.g., program instructions) and, optionally, upload operational orphysiological data stored by IMD 16. Clinician programmer 22 may also beused to perform diagnostics on the uploaded data (e.g., data mining,reviewing trends in the data, and so forth). In this manner, theclinician may periodically interrogate IMD 16 to evaluate efficacy and,if necessary, modify the stimulation parameters.

Like clinician programmer 22, patient programmer 24 may be a handheldcomputing device. Patient programmer 24 may also include a display andinput keys to allow patient 14 to interact with patient programmer 24and IMD 16. In this manner, patient programmer 24 provides patient 14with an interface for limited control of electrical stimulation therapyprovided by IMD 16. For example, patient 14 may use patient programmer24 to start, stop or adjust neurostimulation therapy. In particular,patient programmer 24 may permit patient 14 to adjust stimulationparameters, such as duration, amplitude, pulse width and pulse rate,within an adjustment range specified by the clinician via clinicianprogrammer 22, or select from a library of stored stimulation therapyprograms.

As described in further detail below, patient programmer 24 includes anevent indication button that patient 14 may activate (e.g., bydepressing a button or via a touch screen) in order to provide input toprogrammer 24 indicating that a patient event occurred. The event may bea symptom of the patient's condition. In the case of a seizure disorder,for example, the patient event may be a symptom that leads patient 14 tobelieve that a seizure may occur or the actual onset of a seizure. Asone example, if patient 14 begins detecting an aura, which is a symptomthat may occur prior to the actual onset of the seizure for somepatients, patient 14 may activate the event indication button. An auramay be indicated by a wide range of symptoms including, for example,lightheadedness, dizziness, unusual smells, unusual emotions, alteredvision and hearing, and the like. In response, patient programmer 24 mayrecord the time stamp (i.e., the time and date) the event indicationbutton was activated. Alternatively, the time stamp may be provided byIMD 16. As described in further detail below, in some examples, patientprogrammer 24 may provide a signal to IMD 16 that causes IMD 16 toinitiate therapy delivery or modify at least one therapy parameter(e.g., by shifting to another therapy program group) in response toreceiving the seizure indication from patient 14 via the eventindication button.

Patient programmer 24 may also include other input mechanisms to allowpatient 14 to enter information related to an event. For example, anysuitable input mechanism, such as a keypad, touch screen, a push button,a soft-key, a voice activated command, a means activated by otherphysical interactions, a magnetically triggered switch, a contactdefined by a touch screen, or any other suitable user interface may beused by patient 14 to enter information including, but not limited to,the type or severity of the seizure, the duration of the seizure, theefficacy of a therapy provided during, before or after the seizure, thedrug taken prior to or after the event, and the like. Patient programmer24 may then associate this entered information with an event marker,such as an event indication button press, and store the information inmemory for subsequent downloading and viewing using clinician programmer22, or for later viewing using patient programmer 24. In this way,patient programmer 24 may receive and record information specifying theimpact therapy system 10 may have had on the patient event and/orpatient condition.

IMD 16, clinician programmer 22, and patient programmer 24 maycommunicate via cables or a wireless communication, as shown in FIG. 1.Clinician programmer 22 and patient programmer 24 may, for example,communicate via wireless communication with IMD 16 using RF telemetrytechniques known in the art. Clinician programmer 22 and patientprogrammer 24 also may communicate with each other using any of avariety of local wireless communication techniques, such as RFcommunication according to the 802.11 or Bluetooth specification sets,infrared communication, e.g., according to the IrDA standard, or otherstandard or proprietary telemetry protocols.

FIG. 2 is a block diagram illustrating IMD 16 in greater detail. IMD 16is coupled to leads 20A and 20B, which include electrodes 30A-30D and31A-31D, respectively. Although IMD 16 is coupled directly to leads 20,in other examples, IMD 16 may be indirectly coupled to leads 20, e.g.,via lead extension 18 (FIG. 1). IMD 16 includes therapy module 32,processor 34, memory 36, telemetry module 38, sensing module 40, andpower source 41.

IMD 16 may deliver electrical stimulation therapy to brain 12 of patient14 via electrodes 30A-30D of lead 20A and electrodes 31A-31D of lead 20B(collectively “electrodes 30 and 31”). In the example shown in FIG. 2,implantable medical leads 20 are cylindrical. As previously described,in other examples, leads 20 may be, at least in part, paddle-shaped(i.e., a “paddle” lead). In some examples, electrodes 30, 31 may be ringelectrodes. In other examples, electrodes 30, 31 may be segmented orpartial ring electrodes, each of which extends along an arc less than360 degrees (e.g., 90-120 degrees) around the outer perimeter of therespective lead 20. The use of segmented or partial ring electrodes 30,31 may also reduce the overall power delivered to electrodes 30, 31 byIMD 16 because of the efficient delivery of stimulation to a targetstimulation site by eliminating or minimizing the delivery ofstimulation to unwanted or unnecessary regions within patient 14.

The configuration, type, and number of electrodes 30, 31 illustrated inFIG. 2 are merely one example. Other electrode configurations, types,and quantities are contemplated. For example, IMD 16 may be coupled toone lead with eight electrodes on the lead or three or more leads withthe aid of bifurcated lead extensions.

Electrodes 30, 31 are electrically coupled to a therapy module 32 of IMD16 via conductors within the respective leads 20A, 20B. Each of theelectrodes 30, 31 may be coupled to separate conductors so thatelectrodes 30, 31 may be individually selected, or in some examples, twoor more electrodes 30 and/or two or more electrodes 31 may be coupled toa common conductor. In one example, an implantable signal generator orother stimulation circuitry within therapy module 32 delivers electricalsignals (e.g., pulses or substantially continuous-time signals, such assinusoidal signals) to a target tissue site within patient 14 via atleast some of electrodes 30, 31 under the control of processor 34. Thestimulation energy generated by therapy module 32 may be delivered fromtherapy module 32 to selected electrodes 30, 31 via a switch matrix andconductors carried by the respective lead 20, as controlled by processor34.

Processor 34 may include any one or more of a microprocessor, acontroller, a digital signal processor (DSP), an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA),discrete logic circuitry, or the like. The functions attributed toprocessor 34 herein may be embodied as software, firmware, hardware orany combination thereof.

Therapy module 32 and sensing module 40 are coupled to switching module42. Processor 34 may control switching module 42 to apply thestimulation signals generated by therapy module 32 to selectedcombinations of electrodes 30, 31. In particular, switching module 42couples stimulation signals to selected conductors within leads 20,which, in turn, deliver the stimulation signals across selectedelectrodes 30, 31. In addition, in some examples, processor 34 maycontrol switching module 42 to sense electrical signals via a selectedcombination of electrodes 30, 31.

Therapy module 32 may comprise a single or multi-channel stimulationgenerator. In particular, therapy module 32 may be capable of deliveringa single stimulation pulse, multiple stimulation pulses, or a continuoussignal at a given time via a single electrode combination or multiplestimulation pulses at a given time via multiple electrode combinations.In some examples, however, therapy module 32 and switching module 42 maybe configured to deliver multiple channels on a time-interleaved basis.In this case, switching module 42 serves to time division multiplex theoutput of therapy module 32 across different electrode combinations atdifferent times to deliver multiple programs or channels of stimulationenergy to patient 14.

Processor 34 controls the implantable signal generator within therapymodule 32 to deliver electrical stimulation therapy according toselected therapy parameters. Specifically, processor 34 controls therapymodule 32 to deliver electrical signals with selected voltage or currentamplitudes, pulse widths (if applicable), and rates specified by one ormore therapy programs, which may be arranged into therapy programgroups. In one example, processor 34 controls therapy module 32 todeliver stimulation therapy according to one therapy program group at atime. The therapy programs may be stored within memory 36. In anotherexample, therapy programs are stored within at least one of clinicianprogrammer 22 or patient programmer 24, which transmits the therapyprograms to IMD 16 via telemetry module 38.

Processor 34 may also control therapy module 32 to deliver theelectrical stimulation signals via selected subsets of electrodes 30, 31with selected polarities. For example, electrodes 30, 31 may be combinedin various bipolar or multi-polar combinations to deliver stimulationenergy to selected sites, such as sites within brain 12. Theabove-mentioned switch matrix may be controlled by processor 34 toconfigure electrodes 30, 31 in accordance with a therapy program.

Sensing module 40 is configured to collect, measure, and/or calculatephysiological parameter data for patient 14. For example, sensing module40 may sense bioelectrical signals generated within brain 12 of patient14, which may be used to automatically detect an onset of a seizure or asymptom of a seizure. Examples of seizure predicting algorithms based onEEG signals are discussed in commonly-assigned U.S. Pat. No. 7,006,872,entitled, “CLOSED LOOP NEUROMODULATION FOR SUPPRESSION OF EPILEPTICACTIVITY,” which is incorporated herein by reference in its entirety. Asdescribed in U.S. Pat. No. 7,006,872, in some examples, a seizure may bedetected or predicted based on whether a sensed EEG starts to showsynchrony as opposed to the normal stochastic features.

In other examples, IMD 16 may include other sensing modules configuredto monitor other physiological parameters of patient 14, such as an ECGsignals generated by the patient's heart, temperature, respiratoryactivity, patient motion (e.g., via an accelerometer or piezoelectriccrystal) and the like. In addition, in other examples, therapy system 10may include sensing modules that are separate from IMD 16 andcommunicate with processor 34 of IMD 16 via wireless communicationtechniques or via a cable. As examples, therapy system 10 may include amotion detector external to patient 14 or implanted within patient 14separately from IMD 16. An increase in patient motion or a patientmotion having a particular pattern, as indicated by the motion detector,may indicate the occurrence of a seizure.

IMD 16 also includes a memory 36, which may include any one or morevolatile, non-volatile, magnetic, optical, or electrical media, such asa random access memory (RAM), read-only memory (ROM), non-volatile RAM(NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory,and the like. Memory 36 may store program instructions that, whenexecuted by processor 34, cause IMD 16 to perform the functions ascribedto IMD 16 herein. In addition, memory 36 or another memory or storagedevice may be used to record information relating to patient events.

Telemetry module 38 includes any suitable hardware, firmware, softwareor any combination thereof for communicating with another device, suchas clinician programmer 22 or patient programmer 24 (FIG. 1). Under thecontrol of processor 34, telemetry module 38 may receive downlinktelemetry from and send uplink telemetry to at least one of theprogrammers 22, 24 with the aid of an antenna, which may be internaland/or external. Processor 34 may provide the data to be uplinked to atleast one of the programmers 22, 24 and the control signals for thetelemetry circuit within telemetry module 38, e.g., via an address/databus.

The various components of IMD 16 are coupled to power source 41, whichmay include a rechargeable or non-rechargeable battery. Anon-rechargeable battery may be selected to last for several years,while a rechargeable battery may be inductively charged from an externaldevice, e.g., on a daily or weekly basis.

As previously indicated, a patient may provide input indicating theoccurrence of a patient event by tapping the skin located proximate toIMD 16, as described in commonly-assigned U.S. patent application Ser.No. 11/755,559 to Gerber et al. Accordingly, in other examples of IMD16, IMD 16 may comprise an input mechanism that generates an electricalsignal based on one or more characteristics of tapping of IMD 16 bypatient 14. The characteristics may comprise, for example, the number,frequency, and duration of the tapping. The input mechanism thatgenerates the electrical signal based on the tapping of IMD 16 mayinclude, for example, a multiple or single axis accelerometer or astrain gauge that produces a detectable change in electrical resistancebased on the extent of deformation of the strain gauge.

FIG. 3 is a functional block diagram illustrating components of anexample patient programmer 24, which includes user interface 44,processor 46, telemetry module 48, memory 50, and power source 52.Processor 46 controls user interface 44 and telemetry module 48, andstores and retrieves information and instructions to and from memory 50.Patient programmer 24 may be a dedicated hardware device with dedicatedsoftware for programming of IMD 16. Alternatively, patient programmer 24may be an off-the-shelf computing device running an application thatenables programmer 24 to program IMD 16.

Patient 14 may use patient programmer 24 to select therapy programs(e.g., sets of stimulation parameter values) or groups of programs,generate new therapy programs or program groups, modify one or moretherapy parameter values of a stored therapy program through individualor global adjustments, transmit a new therapy program to a medicaldevice, such as IMD 16 (FIGS. 1 and 2). In addition, as described infurther detail below, patient 14 may use patient programmer 24 to createa log of events, which may, in the case of seizures, includes theoccurrence of a seizure or a symptom of a seizure, such as, but notlimited to, detecting an aura, loss of one or more senses, abnormalsensations (e.g., burning, tingling, pain, and so forth), loss ofbalance or tachycardia (rapid beating of the heart).

Patient 14 may interact with patient programmer 24 via user interface44, which includes user input mechanism 54, event indication button 56,and display 58. User input mechanism 54 may include any suitablemechanism for receiving input from patient 14 or another user. In oneexample, user input mechanism includes an alphanumeric keypad. Inanother example, user input mechanism 54 includes a limited set ofbuttons that are not necessarily associated with alphanumericindicators. For example, the limited set of buttons may includedirectional buttons that permit patient 14 to scroll up or down througha display presented on display 58, select items shown on display 58, aswell as enter information. The limited set of buttons may also include“increment/decrement” buttons in order to increase or decrease astimulation frequency or amplitude of stimulation delivered by IMD 16.

User input mechanism 54 may include any one or more of push buttons,soft-keys, voice activated commands, activated by physical interactions,magnetically triggered, activated upon password authentication pushbuttons, contacts defined by a touch screen, or any other suitable userinterface. In some examples, buttons of user input mechanism 54 may bereprogrammable. That is, during the course of use of patient programmer24, the buttons of user input mechanism 54 may be reprogrammed toprovide different programming functionalities as the needs of patient 14changes or if the type of IMD 16 implanted within patient 14 changes.User input mechanism 54 may be reprogrammed, for example, by clinicianprogrammer 22 (FIG. 1) or another computing device.

Event indication button 56 may be any one or more of a push button,toggle, switch, soft-key, voice activated command, a user inputmechanism activated by physical interaction, magnetically triggered userinput mechanism, a user input mechanism activated upon passwordauthentication push button, a contact defined by a touch screen, or anyother suitable user interface. In the example shown in FIG. 3, eventindication button 56 is a dedicated button that is separate from thebuttons of user input mechanism 54 in order to allow patient 14 toquickly access and activate button 56. In other examples, however, eventindication button 56 may be incorporated with the buttons of user inputmechanism 54. For example, if user input mechanism 54 includes aplurality of alphanumeric buttons, depressing one of the buttons in aparticular pattern or pushing two or more of the buttons simultaneouslymay also trigger the functionality of event indication button 56.

Patient 14 may “activate” event indication button 56 by depressing apush button, soft-key, touching the corresponding portion of a touchscreen of display 58, flipping a switch or using any other suitabletechniques. Event indication button 56 is coupled to processor 46. Afterpatient 14 activates event indication button 56, processor 46 generatesan event marker. The event marker may be a value, flag or signal that isstored by processor 46 within event data 60 of memory 50. If patient 14is afflicted with seizures, the event marker may also be referred to asa “seizure marker.”

In some examples, patient programmer 24 and/or IMD 16 may be configuredto prevent patient 14 from activating event indication button 56,depending on the patient's past use of event indication button 56,lockout timeouts 56, lockout based on the number of button activationsper unit of time, and so forth. For example, a particular number ofevent indication button 56 activations per a particular unit of time maybe clustered together to indicate a single patient event indication.This may help associate a single indication per patient event if thepatient event lasts for a particular duration and patient 14 activatesevent indication button 56 more than once during the same patient event.

Processor 46 may generate a maximum number of event markers perpredetermined unit of time. For example, processor 46 may be configuredto generate one event marker every five minutes. Thus, if patient 14activates event indication button 56 ten times within five minutes,processor 46 may cluster the ten patient event indications together andgenerate one event marker, rather than ten event markers (i.e., oneevent marker per event indication button 56 activation). Any suitablenumber of patient event indications may be clustered together. This mayhelp maintain the quality of information obtained via activation ofevent indication button 56 by, for example, preventing accidentalactivation of event indication button 56 and prevent the counting ofunnecessary number (e.g., more than one) of event indication button 56activations per actual patient event.

In different examples, the event marker generated by processor 46 may beused to evaluate a therapy program implemented by IMD 16 or modify thetherapy delivered by IMD 16, such as by modifying the therapy programimplemented by IMD 16 or restart a therapy cycle. The event marker mayalso result in two or more of these functions described herein. In oneexample, processor 46 logs the date and time of each event marker withinevent data 60 of memory 50. The event marker is indicative of theoccurrence of the event (e.g., the actual or potential occurrence of aseizure as perceived by patient 14). In this way, the event indicationbutton 56 may be used to create an event log, such as a log that detailsthe occurrence of each seizure or seizure symptom. The event log may bestored in memory 50.

In some cases, processor 46 associate the event marker with the currenttherapy program that is being delivered by IMD 16 in order to evaluatethe current therapy program. Processor 46 may determine the currenttherapy program implemented by IMD 16 by interrogating IMD 16 via therespective telemetry modules 38, 48. Alternatively, the current therapyprogram implemented by IMD 16 may be stored within therapy programs 62of memory 50 of patient programmer 24.

If IMD 16 is configured to sense and record physiological parametervalues of patient 14, IMD 16 may transmit the physiological parametervalues to patient programmer 24, and processor 46 may associate theevent marker with the physiological parameter values and store the datawithin event data 60 of memory 50. Alternatively, IMD 16 may receive theevent marker from patient programmer 24 and store the marker along withthe associated physiological parameter values within memory 36 (FIG. 2).In another example, processor 46 of programmer 24 may generate a recordsignal that causes IMD 16 to store the current physiological parametervalues, and, in some cases, the parameter values within a particulartime span prior to receiving the record signal (e.g., about two secondsto about one minute). Patient programmer 24 may also record the date andtime of the event marker, and a clinician may later retrieve the datafrom patient programmer 24 and IMD 16 and associate the event markerwith the patient parameter values, either manually or with the aid of acomputing device, such as clinician programmer 22.

In another example, upon the generation of the event marker, processor46 transmits the event marker to IMD 16 via telemetry module 48, and IMD16 may modify therapy accordingly. For example, in response to receivingthe event marker from patient programmer 24, IMD 16 may initiatetherapy, adjust therapy, or restart a therapy cycle. In this way, theevent marker may be signal for controlling IMD 16. The settings for IMD16 necessary to initiate or restart the therapy cycle (i.e., the therapyadjustment action) may be saved within therapy programs 62 of memory 50or within memory 36 of IMD 16. If the settings are stored within IMD 16,processor 46 may provide instructions to IMD 16 to access and implementthe stored therapy adjustment action.

In some examples, processor 46 may generate different types of eventmarkers that provide different control signals to IMD 16. As an example,a first type of event marker may be a control signal that causes IMD 16to restart a therapy cycle and a second type of event marker may be acontrol signal that causes IMD 16 to switch to a different therapyprogram group. However, the event markers do not necessarily need todirectly provide a control signal. Rather, processor 46 of programmer 24or processor 34 of IMD 16 may generate the necessary control signal.

Event indication button 56, as well as other input mechanisms providedby user input mechanism 54 may be may be designed to help reduceaccidental activation of a programming function. For example, the button56 may be recessed from an outermost surface of the housing of IMD 24.Alternatively or additionally, patient 14 may be required to hold abutton for a predetermined amount of time in order to activate thebutton, and/or there may be a hold function that prevents the buttonsfrom being activated unless the hold function is deactivated. Forexample, the hold function may be activated and deactivated viamanipulation of a slider bar (not shown) or manipulation of a specifiedcombination of buttons. In addition, as described in further detailbelow, processor 46 may prompt patient 14 to confirm an event indicationbutton 56 activation, such that the user input is validated prior to thegeneration of an event marker. As previously described, the event markermay be used to modify therapy delivery to patient 14. Accordingly,confirming that patient 14 did in fact provide input an indication viathe event indication button 56 that a patient event occurred may helpavoid unnecessarily modifying therapy.

Display 58 may include a color or monochrome display screen, such as aliquid crystal display (LCD), light emitting diode (LED) display or anyother suitable type of display. Patient programmer 24 may presentinformation related to stimulation therapy provided by IMD 16, as wellas other information, such as historical data regarding the patient'scondition and past seizure event logs. Processor 46 monitors activityfrom input mechanism 54, and controls display 58 and/or IMD 16 functionaccordingly. In some examples, display 58 may be a touch screen thatenables the user to select options directly from the display. In suchcases, user input mechanism 54 may be eliminated, although patientprogrammer 24 may include both a touch screen and user input mechanism54. In some examples, user interface 44 may also include audio circuitryfor providing audible instructions or sounds to patient 14 and/orreceiving voice commands from patient 14.

Processor 46 may comprise any combination of one or more processorsincluding one or more microprocessors, DSPs, ASICs, FPGAs, or otherequivalent integrated or discrete logic circuitry. Accordingly,processor 46 may include any suitable structure, whether in hardware,software, firmware, or any combination thereof, to perform the functionsascribed herein to processor 46. Memory 50 may include any volatileand/or nonvolatile memory, such as RAM, ROM, EEPROM or flash memory.Memory 50 may also include a removable memory portion that may be usedto provide memory updates or increases in memory capacities. A removablememory may also allow sensitive patient data to be removed beforepatient programmer 24 is used by a different patient.

Memory 50 stores, among other things, event data 60, therapy programs62, and operating software 64. Memory 50 may have any suitablearchitecture. For example, memory 50 may be partitioned to store eventdata 60, therapy programs 62, and operating software 64. Alternatively,event data 60, therapy programs 62, and operating software 64 may eachinclude separate memories that are linked to processor 46.

Therapy programs 62 portion of memory 50 stores data relating to thetherapy programs implemented by IMD 16. In some examples, the actualsettings for the therapy programs, e.g., the stimulation amplitude,pulse rate and pulse width data, are stored within therapy programs 62.In other examples, an indication of each therapy program or group oftherapy programs, e.g., a single value associated with each therapyprogram or group, may be stored within therapy programs 62, an theactual parameters may be stored within memory 36 of IMD 16 (FIG. 2). The“indication” for each therapy program or group may include, for example,alphanumeric indications (e.g., Therapy Program Group A, Therapy ProgramGroup B, and so forth).

As previously described, event data 60 includes information relating tothe patient events, such as the time and date patient 14 activated theseizure indication button 56. Event data 60 may also store correspondingphysiological parameter values (e.g., EEG signals, blood pressure, bodytemperature, and so forth), if therapy system 10 includes a sensingmodule and sensors to sense such physiological parameters. Patientprogrammer 24 may also receive information such as the severity of theseizure, the duration of the seizure, and the type of seizure afterpatient 14 activated event indication button 56. This information mayalso be stored within event data 60 and, in some cases, associated withthe event marker.

Operating software 64 may include instructions executable by processor46 for operating user interface 44, telemetry module 48 and managingpower source 52. Memory 50 may also store any therapy data retrievedfrom IMD 16 during the course of therapy. The clinician may use thistherapy data to determine the progression of the patient's disease inorder to predict or plan a future treatment.

Patient programmer 24 may communicate via wireless telemetry with IMD16, such as using RF communication or proximal inductive interaction.This wireless communication is possible through the use of telemetrymodule 48. Accordingly, telemetry module 48 may be similar to telemetrymodule 38 (FIG. 2) contained within IMD 16. Telemetry module 48 may alsobe configured to communicate with clinician programmer 22 or anothercomputing device via wireless communication techniques, or directcommunication through a wired connection. As previously described,examples of local wireless communication techniques that may be employedto facilitate communication between patient programmer 24 and anothercomputing device include RF communication according to the 802.11 orBluetooth specification sets, infrared communication, e.g., according tothe IrDA standard, or other standard or proprietary telemetry protocols.In this manner, other external devices may be capable of communicatingwith patient programmer 24 without needing to establish a securewireless connection.

Power source 52 delivers operating power to the components of patientprogrammer 24. Power source 52 may include a battery and a powergeneration circuit to produce the operating power. In some examples, thebattery may be rechargeable to allow extended operation. Recharging maybe accomplished by electrically coupling power source 52 to a cradle orplug that is connected to an alternating current (AC) outlet. Inaddition, recharging may be accomplished through proximal inductiveinteraction between an external charger and an inductive charging coilwithin programmer 24. In other examples, traditional batteries (e.g.,nickel cadmium or lithium ion batteries) may be used. In addition,programmer 24 may be directly coupled to an alternating current outletto operate. Power source 52 may include circuitry to monitor powerremaining within a battery. In this manner, user interface 44 mayprovide a current battery level indicator or low battery level indicatorwhen the battery needs to be replaced or recharged. In some cases, powersource 52 may be capable of estimating the remaining time of operationusing the current battery.

User interface 44 may include an alert LED or other suitable alertfeature. In some examples, IMD 16 may send an alert signal to patientprogrammer 24 via the respective telemetry modules 38, 48 to activatethe alert LED and indicate to a user that a problem may be present. Thealert signal may, for example, signify a low battery, a sensedphysiological event, or another problem. For example, if IMD 16 isconfigured to deliver a drug to patient 16 instead of or in addition toelectrical stimulation, the alert feature of user interface 44 ofpatient programmer 24 may be triggered in response to detecting a lowlevel of drug remaining. Activation of the alert feature of patientprogrammer 24 may alert patient 16 to contact a clinician or take otherprecautions. In some examples, patient programmer 24 may forward thealert or an indication of the alert to a remote device in a remotelocation, such as a clinician office.

User interface 44 may also include an LED or another indication (e.g.,via display 58) that provides confirmation to patient 14 that anoperation was carried out or that input via an event indication button56 was received. For example, when event indication button 56 isactivated by patient 14, and a programming signal is sent to IMD 16 toadjust therapy, user interface 44 may activate an LED to providepositive feedback to patient 16 regarding the successfully sentprogramming signal. The alert may also be provided to patient 14 viadisplay 58 instead of or in addition to the alert LED.

In addition, user interface 44 may include a patient notificationfeature that provides negative feedback when patient activates eventindication button 56, but because a telemetry session between patientprogrammer 24 and IMD 16 was unsuccessful, processor 46 did not take anyaction (e.g., adjusting therapy parameters or even generating an eventmarker). Patient 14 may then reactivate event indication button 56.

In some examples, patient programmer 24 may be useful for performingdiagnostic tests. For example, the clinician may program patientprogrammer 24 to prompt patient 14 to perform a test to diagnosereactionary time (e.g., the amount of time it takes patient 14 to push asequence of buttons), visual or auditory tests, and so forth.Furthermore, a clinician may also interact with patient programmer 24.

FIG. 4 is a functional block diagram illustrating components ofclinician programmer 22, which may be similar to patient programmer 24,but does not include event indication button 56. Common referencenumbers are used in FIGS. 3 and 4 to indicate similar components.Clinician programmer 22 may include more features than patientprogrammer 24. For example, while clinician programmer 22 may beconfigured for more advanced programming features than patientprogrammer 24. This may allow a user to modify more therapy parametervalues with clinician programmer 22 than with patient programmer 24.Patient programmer 24 may have a relatively limited ability to modifytherapy parameter values of IMD 16 in order to minimize the possibilitythat patient 14 selects therapy parameters that are harmful to patient14. Similarly, clinician programmer 22 may conduct more advanceddiagnostics of IMD 16 than patient programmer 24.

As described in further detail below, a processor of clinicianprogrammer 22 may interrogate IMD 16 and/or patient programmer 24 toretrieve any collected information stored within memories 36, 50, suchas event markers, physiological parameter values, and informationassociated with respective event markers, which may include informationreceived from patient 14.

FIG. 5 is a schematic plan view of an example patient programmer 24,which includes event indication button 56, display 58, housing 66, powerbutton 68, display contrast controls 70A and 70B, and various input keys72A, 72B, 74, and 76. Programmer 24 is a handheld computing device thatpatient 14 may carry in order to record event occurrences or otherwiseadjust therapy delivered by IMD 16. Programmer 24 includes outer housing66, which encloses circuitry necessary for programmer 24 to operate.Housing 66 may be constructed of a polymer, metal alloy, composite, orcombination material suitable to protect and contain components ofprogrammer 24. In addition, housing 66 may be partially or completelysealed such that fluids, gases, or other elements may not penetrate thehousing and affect components of programmer 24 contained therein.

Power button 68 turns programmer 24 on or off. Programmer 24 may includesafety features to prevent programmer 24 from shutting down during atelemetry session with IMD 16 or another device in order to prevent theloss of transmitted data or the stalling of normal operation.Alternatively, programmer 24 and IMD 16 may include instructions thathandle possible unplanned telemetry interruptions, such as interruptionsattributable to battery failure or inadvertent device shutdown. WhileIMD 16 is primarily referred to throughout the discussion of FIG. 5, inother examples, programmer 24 may be configured to communicate with oneor more other medical devices. Furthermore, while patient 14 isprimarily referred to throughout the discussion of FIG. 5, in otherexamples, other users may use programmer 24.

As previously described, display 58 may include an LCD or another typeof monochrome or color display capable of presenting information topatient 14. Contrast buttons 70A and 70B may be used to control thecontrast of display 124. Display 58 may provide information regardingthe current therapy program being implemented by IMD 16 and theoperational status of programmer 24. In the example shown in FIG. 5,user interface 78 of patient programmer 24 is presenting a Seizure EventSummary page on display 58, which presents the average number of eventmarkers received by patient programmer 24 via button 56 during thesession lasting from Feb. 4, 2007 (02.04.2007) to May 12, 2007(05.12.07). However, other displays of information are alsocontemplated. For example, display 58 may present a user interface 78that indicates an event marker was generated and logged. As anotherexample, display 58 may present a user interface 78 that prompts patient78 to manually enter information about the seizure occurrence, such asthe type, severity or duration of the seizure, or the efficacy of thetherapy. In addition, display 58 may present information about thestored therapy program groups, and permit patient 14 to modify theparameters within certain ranges predetermined by the clinician. Userinterface 78 may be, for example, a graphical user interface.

Programmer 24 also includes decrease button 72A, increase button 72B,control pad 74, and select button 76, which are all a part of user inputmechanism 54 (FIG. 3). Control pad 74 allows patient 14 to navigatethrough items presented on display 58. Patient 14 may press control pad74 on any of arrows 75A-75D in order to move between items presented ondisplay 58 or move to another screen of user interface 78 presented byprocessor 34 (FIG. 3) not currently shown by display 58. For example,patient 14 may depress or otherwise activate arrows 75B and 75D tonavigate between available user interface 78 screens that may bepresented on display 58. Patient 14 may press select button 76 to selectany highlighted element in user interface 78. In some examples, themiddle portion of control pad 74 may provide a “select” button thatenables patient 14 to select a particular item presented on display 58,such as an item that is highlighted on display 58. In other examples,scroll bars, a touch pad, scroll wheel, individual buttons, or ajoystick may perform the complete or partial function of control pad 74.

Decrease button 72A and increase button 72B provide input mechanisms forpatient 14. In general, depressing decrease button 72A one or more timesmay decrease the value of a highlighted therapy parameter, such asamplitude, pulse width or pulse rate, and depressing increase button 72Bone or more times may increase the value of a highlighted therapyparameter, such as an amplitude of stimulation therapy, or, in theexample of drug delivery, the dosage delivered during a bolus. Theincrement/decrement function of buttons 72A and 72B may be limited topatient-specific adjustment ranges defined by a clinician (e.g., viaclinician programmer 22 of FIG. 1) in order to ensure that the therapydelivered by IMD 16 stays within a safe, clinician-approved range.

While buttons 72A and 72B may be used to control the value of anytherapy parameter, patient 14 may also utilize buttons 72A and 72B toselect particular programs during a therapy session. In other examples,control pad 74 may be the only input that patient 14 may use to navigatethrough the screens and menus of programmer 24.

Programmer 24 may take other shapes or sizes not described herein. Forexample, programmer 24 may take the form of a clam-shell shape, similarto cellular phone designs. When programmer 24 is closed, some or allelements of the user interface may be protected within the programmer.When programmer 24 is open, one side of the programmer may contain adisplay while the other side may contain input mechanisms. In any shape,programmer 24 may be capable of performing the requirements describedherein.

Furthermore, in alternative examples, the buttons of programmer 24 mayperform different functions than the functions provided in FIG. 5 as anexample. In addition, other examples of programmer 24 may includedifferent button layouts or number of buttons. For example, display 58may be a touch screen that incorporates some or all of the user inputmechanism 54 functionality.

Event indication button 56 is located near buttons 72A and 72B. However,in other examples, event indication button 56 may be located at another,discrete location relative to programmer housing 66. In some examples,event indication button 56 is a different size, color and/or a differenttexture than the other buttons of programmer 24, or otherwisedistinguished from the other buttons of programmer 24 in order to enablepatient 14 to easily locate event indication button 56. Event indicationbutton 56 may also be sized to permit relatively fast location andactivation of button 56, particularly with patients with limiteddexterity. When a patient event occurs, the ability for patient 14 torelatively quickly locate and activate event indication button 56 may beimportant. This may be particularly true if activation of eventindication button 56 triggers or otherwise controls therapy.

FIG. 6A is a flow diagram illustrating an example technique formodifying therapy delivery to patient 14 based on receiving anindication of a patient event. Upon detecting a symptom indicative of aseizure or another patient event, patient 14 may activate eventindication button 56. Processor 46 of patient programmer 24 (FIG. 3) iscoupled to button 56, and, therefore, receives the indication of theevent (80). In other examples, the patient event may be automaticallydetected by processor 46 or by processor 34 of IMD 16 based on signalsfrom sensing module 40 of IMD 16 (FIG. 2). In some examples, processor34 of IMD 16 may receive the signals from sensing module 40, generatethe patient event indication, and transmit the indication to processor46 of patient programmer 24. In other examples, processor 46 may receivethe signals from sensing module 40 and generate the patient eventindication.

After receiving the indication of the patient event (80), processor 46may generate an event marker (82). As previously described, the eventmarker may be a flag, value or other signal. Processor 46 may record thedate and time of the event marker within event data 60 of memory 50(84), which is typically the date and time that processor 46 generatedthe event marker.

Processor 46 may associate the event marker with a therapy program groupthat is currently implemented by IMD 16 (86). In some examples,processor 46 may interrogate IMD 16 to determine which program group IMD16 is currently delivering therapy, or processor 46 may track thecurrent program group within program group 62 portion of memory 50.Depending upon the type of IMD 16 or the mode of operation of IMD 16, insome cases, processor 46 associates the event marker with a singletherapy program, rather than a program group, which may include one ormore therapy programs. Thus, while program groups are primarily referredto throughout the description of FIGS. 6A and 6B, in other examples,processor 46 may associate the event marker with a therapy program.

Patient 14 may not be able to activate event indication button 56 atexactly the same time that the event occurs. For example, if the patientevent is a seizure, patient 14 may not be able to activate eventindication button 56 until after patient 14 recovers from the seizure.Depending upon the duration and severity of the seizure, recovery maytake minutes or even hours. Thus, processor 46 may associate the eventmarker with the most recently implemented therapy program or thecurrently implemented therapy program. Alternatively, programmer 24 mayprovide patient 14 with the opportunity to modify the date and time ofthe event marker. If patient 14 knew, for example, that the eventoccurred at least two hours before patient 14 actually activated eventindication button 56, patient 14 may modify the time of the event markerby at least two hours via user input mechanism 54 of patient programmer24 (FIG. 3).

Processor 46 may determine an event metric for the current therapyprogram group (88). The event metric may be any suitable metric that isindicative of the relative number of event markers associated with theprogram group, and is not necessarily limited to the gross number ofevent markers associated with the program group. In the case of seizuremarkers, the event metric may also be referred to as a “seizure metric.”In one example, the event metric is a total number of event markersassociated with the current program group. In another example, the eventmetric is a number of event markers associated with the current programgroup per unit of time. For example, the event metric may be the averagenumber of event markers for the particular program group per hour, perday, per week, per month, and so forth. The average may be taken over acertain period of time (e.g., clinician-specified period of time) orover the entire time in which IMD 16 has delivered therapy according tothe current therapy program.

In other examples, an event metric may include a change from thepatient's baseline condition, and the threshold may be a percentage.Thus, in some cases, processor 46 may evaluate a therapy program basedon a percent change from a baseline condition. The patient's baselinecondition may be, for example, the average number of patient events,which are indicative of a seizure during an initial sample period. Thebaseline condition may be automatically determined during a period inwhich IMD 16 is disabled. Alternatively, the clinician may select thebaseline condition as the total number of events per unit of time thatis acceptable. As an example of the percent change from the patient'sbaseline condition, if the baseline condition is two seizure occurrencesduring a day, and patient 14 experiences one seizure occurrence in aday, the percent change is approximately 50% (e.g., which may be a“responder rate”). In another example, the baseline condition may be theaverage number of events experienced by the patient prior to theimplementation of therapy system 10. Thus, little to no change from thatnumber indicates the therapy program is not effective in managing thepatient's condition.

The baseline condition may be specific to the particular patient 14 ormay be generalized for a population of two or more patients. Thepercentage change from the patient's baseline condition provides auseful metric that indicates the patient's relative condition, ratherthan an objective evaluation of the patient's condition (e.g., which maybe achieved with the metrics described above). For example, if patient14 exhibits frequent grand tonic clonic seizures, which are relativelysevere, prior to the implementation of therapy system 10, and after theimplementation of system 10, patient 14 exhibits frequent absenceseizures (petit mal) seizures, which are less severe than grand tonicclonic seizures, the patient's condition has improved because the typeof seizures have changed. However, if patient 14 exhibits infrequentabsence (petit mal) seizures prior to the implementation of therapysystem 10, and after the implementation of system 10, patient 14exhibits infrequent grand tonic clonic, the patient's condition may beless serious than a patient who is afflicted with frequent grand tonicclonic seizures. However, the percent change from the patient's baselinecondition may indicate the patient's condition has worsened.

As described in further detail below, processor 46 may modify therapydelivery to patient 14, e.g., implement a switch from a first therapyprogram group to another therapy program group, if the deviation fromthe patient's baseline condition falls below a threshold. For example,if the patient's condition improves drastically, such that the percentchange from the patient's condition falls below a threshold, processor46 may provide a signal to IMD 16, which causes IMD 16 to switch therapydelivery to another therapy program that may be less intense orotherwise adjust at least one therapy parameter value.

In some examples, an upper limit threshold for modifying therapydelivery to patient 14 and a lower limit threshold may be implemented.If the event metric indicates the patient's condition has declined,i.e., by exceeding either the upper limit threshold, processor 46 mayimplement a switch to another program that may provide more effectivetherapy or increase the intensity of stimulation provided by the currenttherapy program. On the other hand, if the event metric indicates thepatient's condition has improved, i.e., by exceeding the lower limitthreshold, processor 46 may implement a switch to another therapyprogram that may provide less intensity. In this way, processor 46 maydirect the therapy delivered by IMD 16 to the patient's condition. Thismay help reduce power consumed by IMD 16 by providing the minimum levelof therapy necessary to maintain the patient's condition within acertain range of a baseline condition.

In examples in which the indication of the patient event is generatedupon activation of event indication button 56 of patient programmer 24by patient 14, the unit of time over which the patient event indicationsare counted or averaged may be adjusted to account for periods of timein which patient 14 is unable to provide input via event indicationbutton 56. For example, if patient 14 is in a hospital and unable tointeract with patient programmer 24, leaves patient programmer 24 athome during a vacation, or otherwise is unable to access eventindication button 56, processor 46 of patient programmer 24 may blankout the time in which patient 14 does not have access to patientprogrammer 24. That is, processor 46 may consider the time in whichpatient 14 did not have access to patient programmer 24 when determiningan event metric.

The amount of time that is blanked out may be determined based on inputfrom a user, such as patient 14. For example, prior to or after theperiod of time in which patient 14 does not have access to eventindication button 56, patient 14 may provide input via user interface 44of patient programmer 24 (FIG. 3), indicating that a particular periodof time (a “suspension period”) should be blocked out or the eventindication feature of programmer 24 should be suspended for a particularperiod of time. User interface 44 may, for example, present a calendar,pull down list or other graphical user interface on display 58 thatenables patient 14 to easily enter the time period that should beblocked out.

Blocking out a period of time in which patient 14 did not have access toevent indication button 56 may be useful for more accurately andprecisely determining an event metric. For example, if patient 14 doesnot have access to event indication button 56, and, therefore, does notindicate the occurrence of a patient event for a particular period oftime (e.g., a few days), processor 46 of patient programmer 24 maymisinterpret the lack of input as an indication that the patient'scondition is improved. As another example, if the time in which patient14 did not have access to patient programmer 24 is not accounted for,the frequency of button presses may be misrepresented. For example, ifpatient provides 30 button presses over a period of 30 days, but patient14 did not have access to patient programmer 24 for 10 of those days,the frequency of patient event indications may be inaccurately presentedas 30 button presses over 30 days, whereas the correct patient eventindication count would be 30 button presses over 20 days. As describedin further detail below, the lack of input indicating a patient event ora lower average of patient event indications per unit of time maytrigger an adjustment to the therapy delivered to patient 14, such as aswitch to a less intense therapy program.

After calculating the event metric for the current therapy programimplemented by IMD 16, processor 46 may determine whether the eventmetric is greater than or equal to a threshold value (90). However, inother examples, depending upon the type of metric, processor 46 maydetermine whether the event metric is equal to or less than a thresholdvalue. The threshold value may be stored within memory 50 of patientprogrammer 24 or memory 36 of IMD 16. The threshold value may bedetermined by the clinician or another party, such as the manufacturerof IMD 16. In examples in which the event metric comprises a number ofevent markers, the threshold value may reflect the total number ofevents that patient 14 may experience before a change to the therapyprogram is desirable. Thus, comparing the number of event markers to thethreshold may indicate whether the current therapy program is consideredrelatively effective or ineffective. As previously described, the eventmarkers may indicate each input from patient 14 indicating theoccurrence of an event or two or more patient inputs (e.g., the eventindication button 56 presses) may be clustered together and associatedwith a single event marker if the patient inputs occur within aparticular window of time.

In another example, the threshold value may reflect the frequency ofseizure occurrences that patient 14 may experience before a modificationto the therapy program is considered desirable. In this example, thetherapy metric that indicates the number of event markers per unit oftime may be compared to a threshold value that also includes a number ofevent markers per unit of time. If necessary, processor 46 may modifythe therapy metric or the threshold value so that each includes the sameunit of time.

In another example, the threshold value may reflect the acceptablepercentage change from a baseline condition. In this example, thetherapy metric that indicates percentage change from the baselinecondition may be compared to a threshold percentage value. If thebaseline condition is the average number of seizure occurrencesexperienced by the patient prior to the implementation of therapy system10, a percentage change (decrease in seizure frequency) from a baselinecondition that is less than a predetermined responder threshold value(e.g., 50%) may indicate therapy system 10 is ineffective.

In examples in which IMD 16 delivers therapy to patient 14 according todifferent therapy programs or program groups, a different thresholdvalue may be associated with two or more therapy programs or groups. Forexample, a first therapy program group may include a higher thresholdthan a second therapy program group. As described in further detailbelow, therapy program groups may be arranged in a particular sequencebased on the likelihood of success of the therapy program group. Thus, afirst therapy program group may have a lower intensity of stimulation(e.g., a lower current or voltage amplitude) than a second therapyprogram group. In this case, it may be useful to set a lower thresholdvalue for the second therapy program group because the program groupwith the higher intensity should theoretically be more effective, and,accordingly, is considered less effective at a threshold lower than thethreshold for concluding that the first therapy group with a lowerintensity was ineffective.

The relevant threshold may also be set using a procedure, or a variantthereof, of a statistical process in which the threshold is adjusted atperiodic points in time, rather than being fixed, based on variations inthe frequency of the occurrence of the patient events. An example of asuitable statistical process is described in commonly-assigned U.S. Pat.No. 6,155,267 to Nelson, entitled, “IMPLANTABLE MEDICAL DEVICEMONITORING METHOD AND SYSTEM REGARDING THE SAME,” which issued on Dec.5, 2000 and is hereby incorporated by reference in its entirety.

If the event metric is less than the threshold value, processor 46 doesnot take any action, and waits to receive an indication of a potentialseizure onset (or another patient event) via an event indication button56 (80). If the event metric is greater than or equal to the thresholdvalue, processor 46 may instruct 1 MB 16 to adjust therapy delivery topatient (92). In this way, patient 14 may directly affect therapydelivered by IMD 16 by depressing event indication button 56. Patientprogrammer 24 may notify patient 14 of the change in therapy programs,e.g., via display 58, by generating an audible sound, vibrating orproviding another sensory cue.

In some examples, processor 46 may adjust therapy delivery to patient 14by instructing IMD 16 to switch to another therapy program group (ortherapy program). For example, processor 46 may instruct 1 MB 16 toswitch to the next program group stored within memory 36, or processor46 may send the actual program group parameter values to IMD 16. Theclinician may order the therapy program groups in a random sequence orin a sequence that reflects the likelihood of treatment success. In somecases, a clinician may preorder the therapy program groups in aparticular sequence, which may be stored within therapy programs 62 ofmemory 50 of patient programmer 24 or within memory 36 of IMD 16.

Any number of therapy groups may be stored within patient programmer 24or IMD 16, such as two, three, four or more. As one example of asequence that reflects the likelihood of treatment success, theclinician may order four therapy program groups in the following order:Therapy Group A, Therapy Group B, Therapy Group C, and Therapy Group D.The likelihood of success of each therapy group may be based onclinician knowledge of the therapy parameter values and the effect on apatient from modifying each therapy parameter. Therapy Groups A an B maybe substantially similar, but Therapy Group B may include a highervoltage or current amplitude than Group A. Thus, if Therapy Group Aproves ineffective (e.g., because the event metric based on the eventmarkers is greater than or equal to the threshold), implementing Group Bto increase the voltage or current amplitude of stimulation may providemore effective therapy to patient 14.

Therapy Group C may be substantially similar to Therapy Group B, but mayinclude a different pulse width. Again, if Therapy Group B provesineffective, implementing Group C to change the pulse width may providemore effective therapy to patient 14. Therapy Group D may besubstantially similar to Therapy Group C, but may include a differentstimulation frequency. If Therapy Group C proves ineffective,implementing Group D to change the stimulation frequency may providemore effective therapy to patient 14. In this way, the clinician maymodify a therapy delivery to patient 14 without requiring patient 14 tovisit the clinician's office each time a therapy group appears to beineffective.

In some cases, it may be desirable for patient 14 to test a group oftherapy programs for a particular time period, and/or to limit the timeat which a therapy program group is switched. This may help provide arelatively predictable and smooth transition between therapy groups. Theclinician or another user may determine the fixed period of time. Insome examples, the fixed time period may define a trial period duringwhich IMD 16 delivers stimulation according to a particular a therapyprogram to test the therapy program. For example, the clinician maydetermine that processor 46 should only evaluate a current therapyprogram every 30 days, although other time periods are also possible. Inother examples, the fixed time period may define the intervals at whichprocessor 46 may evaluate a therapy program group based on the eventmarkers and control the switch from one therapy group to another if thetherapy program group appears to be ineffective in managing thepatient's condition. For example, the fixed time period may define theminimum interval at which a therapy program may be switched.

In some examples, rather than switching between predetermined therapygroups, processor 46 may adjust therapy delivery to patient (92) bycontrolling the modification to one or more therapy parameter values. Inexamples in which IMD 16 delivers electrical stimulation therapy topatient 14, the therapy parameter values may comprise the therapyparameters may include an electrode combination, and an amplitude, whichmay be a current or voltage amplitude, and, in examples in which IMD 16delivers stimulation pulses to patient 14, a pulse width, and a pulserate for stimulation signals to be delivered to the patient. In examplesin which IMD 16 delivers a therapeutic agent to patient 14, the therapyparameters may include a dose (e.g., a bolus or a group of boluses)size, a frequency of bolus delivery, a concentration of a therapeuticagent in the bolus, a type of therapeutic agent to be delivered to thepatient (if the medical device is configured to deliver more than onetype of agent), a lock-out interval, and so forth.

A clinician or another party may define an acceptable range of therapyparameter values for IMD 16. The range of therapy parameter values maybe specific to patient 14 or may be applicable to a group or class ofpatients. Ranges of values for one or more therapy parameters may bestored within memory 50 of patient programmer 24, memory 36 of IMD 16(FIG. 2) or a memory of another device. Programmer 46 may be programmedto adjust therapy parameter values within the stored range in order toadjust therapy (92), rather than selecting from discrete programs.

In examples in which IMD 16 operates in an open loop system 10, theinput from event indication button 56 may modify the therapy parametersused by IMD 16, thereby resulting in a modified open loop therapy system10. The technique shown in FIGS. 6A and 6B may also be used with aclosed loop therapy system.

FIG. 6B is a flow diagram illustrating another example technique formodifying therapy delivery to patient 14 based on receiving anindication of a patient event. Processor 46 may start a time period forevaluating a particular therapy program (93). As previously described,this time period may be selected by a clinician or another user. Aninternal clock within patient programmer 24 or IMD 16 may be used tostart the time period and as a counter to track the time period. Uponreceiving an indication of a patient event (80), processor 46 generatesan event marker (82), records the date and time of the event markerwithin event data 60 of memory 50 (84), and associates the event markerwith a therapy program group that is currently implemented by IMD 16(86). Processor 46 may determine whether the time period has ended (94),e.g., by comparing the clock count with a threshold.

If the time period has not ended, processor 46 may continue to wait foran indication of a patient event (80). If the time period has ended,however, processor 46 may determine an event metric for the currenttherapy program group (88), compare the metric to a threshold (90), andadjust therapy delivery to patient 14 (e.g., switch to another therapyprogram group or modifying one or more therapy parameter values) if themetric exceeds the threshold (92), as described with respect to FIG. 6A.On the other hand, if the metric does not exceed the threshold (92),indicating that the therapy program group is effective for patient 14 orat least is not yet determined to be ineffective, processor 46 mayrestart the time period (93).

The technique shown in FIG. 6B is useful for controlling the intervalsat which a therapy program group for IMD 16 is changed. Rather thanmodifying therapy delivery to patient 14 each time an event metricindicates the program group is ineffective, processor 46 controls theswitch to another the therapy program group at predefined intervals,which may be defined by the time period selected by the clinician.

In other examples, processor 46 may implement a technique that is ahybrid of the techniques shown in FIGS. 6A and 6B. For example, afterdetermining an event metric (88), processor 46 may determine whether thetime period has ended (94) and whether the event metric is greater thanor equal to a threshold (90). If either of these conditions is met,processor 46 may control IMD 16 to modify therapy delivery to patient 14(92). This hybrid technique may be useful for a trial period in whichtherapy system 10 is trialed to determine its efficacy for patient 14,as well as a trial period during which a plurality of therapy programgroups are trialed for the time period.

While FIGS. 6A and 6B are described primarily with reference toreceiving of an indication of a potential seizure via an eventindication button 56, in other examples, processor 46 may receive anindication of a potential seizure without patient intervention. Forexample, IMD 16 or another medical device may be configured to monitorone or more physiological parameters of patient 14, such as an EEGsignal, ECG signal, or an electrocorticogram (ECoG) signal within thethalamus, seizure onset zone or one or more other regions of brain 12 ofpatient 14. The seizure onset zone may include, for example, acaudatenucleus, locus coeruleus, cerebellum, subthalamic nucleus, cingulate,substantia nigra, thalamic structures (e.g., the centromedian nucleus,centrolateral nucleus, and dorsomedial nucleus), brain lobe (e.g.,frontal, temporal, parietal and occipital lobes), premotor cortex or MILstructures of brain 12.

Under the control of processor 46, patient programmer 24 may obtain theEEG data, ECoG data or other data indicative of seizures using knowntechniques and implement a seizure detection algorithm to determine whena seizure occurred. For example, the amplitude waveform of the EEGsignal may be compared to a template. Processor 46 may generate aseizure indication (or another event indication), which may act as asurrogate to event marker. The seizure indication may include a timestamp. Thus, processor 46 may not need to generate an event marker.Alternatively, IMD 16 or the medical device configured to sense thephysiological parameter value may process the physiological parameter todetermine when a seizure occurred and transmit a seizure indication toprocessor 46 of patient programmer 24.

Many existing seizure prediction systems and methods rely on EEG data todetermine when a seizure has started. In those existing systems, therapymay be delivered when the EEG data exhibits a certain characteristic.For example, in one seizure predicting procedure discussed incommonly-assigned U.S. Pat. No. 7,006,872, entitled, “CLOSED LOOPNEUROMODULATION FOR SUPPRESSION OF EPILEPTIC ACTIVITY,” a seizure ispredicted based on whether a sensed EEG starts to show synchrony asopposed to the normal stochastic features.

In some examples in which a physiological parameter of patient 14 ismonitored, the physiological parameter does not provide an input thatdirectly controls therapy delivery by IMD 16 if IMD 16 is configured foropen loop therapy or modified open loop therapy. However, thephysiological parameter may be useful for later analysis by a clinician.Physiological parameter values sensed at the time the event marker wasgenerated, and, in some cases, within a certain time period prior to andafter the time stamp of the event marker, may be stored and associatedwith the event marker. Of course, if desired, the systems and methodsdescribed herein may also be used with closed loop therapy systems, suchas closed loop systems in which an input (e.g., a physiologicalparameter value) directly controls therapy delivery.

In examples in which the patient event indication is generated based onsensed physiological parameter values, therapy may be automaticallydelivered to patient 14. Thus, the technique shown in FIGS. 6A and 6Bmay also be used with a closed loop therapy system. The therapy programsmay be evaluated for efficacy using the technique shown in FIGS. 6A and6B regardless of whether therapy system 10 is an open-loop, modifiedopen-loop, closed-loop, modified closed-loop, responsive or other typesof therapy systems.

FIG. 7 is a flow diagram illustrating an example technique for adjustingtherapy delivery to patient 14 based on patient event indications. Asdescribed with respect to FIG. 6, processor 46 of patient programmer 24may receive an indication of a patient event (80). Processor 46 may alsodetermine type and/or severity of the patient event (96). The severityof the patient event may be subjective, e.g., from the perspective ofpatient 14, or may be more objective, e.g., may be based on a durationof the patient event.

In some examples, processor 46 may present a graphical user interface ondisplay 58 (FIG. 3) that enables patient 14 to input informationrelating to the type and/or severity of the patient event. As anexample, if the patient event is related to a seizure, the graphicaluser interface may present a list of seizure symptoms or seizure typesand/or severity ratings. For example, the severity ratings may bepresented on a scale of 1-10, whereby 10 is the most severe, or a listof “mild,” “moderate,” and “severe” ratings. Seizure symptoms or typespresented on display 58 of patient programmer 24 may include, forexample, absence seizures, myoclonic seizures, clonic seizures, tonicseizures, tonic clonic seizures, atonic seizures, partial seizures(simple and complex), secondary generalized seizures, and primarilygeneralized seizures.

In examples in which the patient event is automatically detected viainput from sensing module 40 of IMD 16 (FIG. 2), the severity and typeof patient event may be automatically determined. For example, if aseizure is automatically detected based on EEG signals detected bysensing module 40, processor 46 of patient programmer 24 or processor 34of IMD 16 may compare the amplitude of the EEG signal or pattern of theEEG signal to a plurality of thresholds or templates that are eachassociated with a respective type or severity of a seizure.

Processor 46 may generate an event marker based on the type and/orseverity of the patient event (98). In some examples, the date and timethe event marker may be stored with the event marker in memory 50 ofpatient programmer 24 (FIG. 3) or a memory of another device. Processor46 may generate different types of event markers that indicate the typeand/or severity of the patient event. In the example shown in FIG. 7,the event marker comprises a numerical rating that differs based on thetype and/or severity of the patient event. A higher numerical rating mayindicate a more severe type of patient event (e.g., a tonic clonicseizure may have a higher number marker than an absence seizure).Similarly, a higher numerical rating may indicate a more severe patientevent (e.g., a “severe” rating for a particular patient event may have ahigher number event marker than a “mild” rating for the same type ofpatient event).

Processor 46 may associate the event marker with the therapy programgroup (100) within memory 50 of programmer 24 or a memory of anotherdevice. Processor 46 may determine an event metric for the currenttherapy program or therapy group (102). In the example shown in FIG. 7,an event metric comprises an event score, which generally indicates thetype and/or severity of patient events associated with the currenttherapy program or group. As previously indicated, the current therapyprogram or program group may include the therapy program defining thetherapy parameter values with which IMD 16 was delivering therapy topatient 14 at the time the most recent event marker was generated. Insome examples, the event score may include the total value of thenumerical ratings of the event markers associated with the currenttherapy program or group. In other examples, the event score may includethe average numerical rating for the event markers associated with thecurrent therapy program or group.

Processor 46 may compare the event score to a threshold value that isstored within memory 50 of programmer 24 or a memory of another device,such as IMD 16 (104). The threshold may indicate the threshold eventscore at which a therapy program or group is deemed to be ineffective.If the event score is greater than or equal to the threshold (104),processor 46 may adjust therapy delivery to patient (92). On the otherhand, if the event score is less than the threshold, processor 46 maycontinue receiving indications of patient events (80) until the scoreexceeds the threshold.

The technique shown in FIG. 7 enables patient event indications to beweighed based on the type and/or severity of the patient events. Ratherthan counting the gross number or average of patient event indicationsassociated with a therapy program or group, the technique shown in FIG.7 provides a more robust technique for adjusting therapy delivery topatient 14 based on the types and/or severity of patient events thatoccur during therapy delivery according to the current therapy programor group.

FIG. 8 is a flow diagram illustrating an example technique forevaluating a therapy program. Just as in the technique shown in FIG. 8,processor 46 of patient programmer 24 may receive an indication of apatient event (80), generate an event marker (82), record the date andtime of the event marker within memory 50 (84), and associate the eventmarker with a therapy program group (86). Processor 46 may also storethe event marker and associated program group within memory 50 (106).Processor 46 may evaluate the efficacy of each therapy program groupbased on the total number or frequency of event markers or otherrelevant information based on the event markers (108). For example,processor 46 may determine whether a particular therapy program groupprovided more effective therapy for patient 14 at a particular timeduring the day than another therapy program group. On this basis,processor 46 may record data that provides an indication of efficacy.Alternatively, the clinician may access the information stored withinpatient programmer 24, e.g., by downloading information from patientprogrammer 24 into clinician programmer 22, and evaluate the informationmanually or with the aid of a computing device (e.g., clinicianprogrammer 22).

FIG. 9 is a flow diagram illustrating an example technique for modifyingtherapy delivered by IMD 16 based on patient input received via eventindication button 56 of patient programmer 24. The technique shown inFIG. 9 is useful for modifying an open loop or modified open looptherapy system. The modified open loop therapy system may be, forexample, an open loop system that switches between therapy programgroups or adjust at least one stimulation parameter value (or othertherapy parameter value) if an event metric indicates the currenttherapy program is relatively ineffective. Thus, the technique shown inFIG. 9 may be used with the techniques shown in FIGS. 6A-8, in which theevent markers generated when patient activates event indication button56 or programmer 24 otherwise receives an indication a patient eventoccurred is used to evaluate a therapy program or switch between therapyprograms. However, the technique shown in FIG. 9 may be usedindependently of the techniques shown in FIGS. 6A-8.

Processor 46 of patient programmer 24 receives an indication that apatient event occurred, e.g., via event indication button 56 (80) orgenerates the patient event indication based on signals from sensingmodule 40. Processor 46 may generate an event marker (82), and, in someexamples, record the date and time the event marker was generated (84).Upon generating the event marker (82), processor 46 may determinewhether therapy is currently being delivered to patient 14 (110). Forexample, in the case of IMD 16, processor 46 may determine whetherstimulation is currently being delivered to patient 14. In examples inwhich IMD 16 operates in an open-loop, processor 46 may determinewhether IMD 16 is currently in an on-cycle of stimulation or in anoff-cycle during which no stimulation is delivered to patient 14 (110).

If therapy is not currently being delivered, i.e., IMD 16 is in theoff-cycle, at approximately the same time patient 14 activates eventindication button 56, processor 46 provides a control signal to IMD 16or otherwise controls IMD 16 to initiate therapy delivery (112). Asdescribed in further detail with reference to FIGS. 11A-11D, initiatingtherapy delivery (112) may restart a therapy cycle. For example, if theon-cycle is about one minute and the off-cycle is about five minutes,and processor 46 initiates therapy delivery during a five minuteoff-cycle, the five minute off-cycle is shortened, and the one minuteon-cycle is initiated. Thereafter, IMD 16 may continue implementing thetherapy cycle including a normal one minute on-cycle and five minuteoff-cycle, at least until another indication of a patient event isreceived (80) by patient programmer 24 or IMD 16.

If therapy is currently being delivered to patient (110) atapproximately the same time patient 14 activates event indication button56, i.e., IMD 16 is currently in an on-cycle, processor 46 provides acontrol signal to IMD 16 or otherwise controls IMD 16 restart theon-cycle, and, in effect, restart the therapy cycle. For example, usingthe therapy cycle including a one minute on-cycle and a five minuteoff-cycle as an example, if patient 14 activates event indication button56 during the one minute on-cycle, processor 46 provides a controlsignal to IMD 16 or otherwise controls IMD 16 to restart the one minuteon-cycle (114), regardless of the point during the one minutestimulation session the indication of the patient event was received.The event marker generated by processor 46 may act as the control signalor processor 46 may generate another control signal. In this way,patient 14 may directly affect the therapy cycle implemented by IMD 16by activating event indication button 56. Furthermore, because IMD 16maintains the same timing between an on-cycle and off-cycle, but onlyinitiates or restarts the cycle upon generation of the event marker byprocessor 46, therapy system 10 remains an open loop system thatprovides stimulation in a regular cycle. Thus, after the on-cycle isrestarted, IMD 16 continues implementing the normal therapy cycle.

In the technique shown in FIG. 9, processor 46 controls IMD 16 torestart the therapy cycle without requiring patient programmer 24 toshut down and restart. Thus, the restarting of the therapy cycle inresponse to patient activation of event indication button 56 may berelatively quick and responsive to the patient's input.

FIG. 10 is a flow diagram illustrating another example technique formodifying therapy delivered by IMD 16 based on patient input receivedvia event indication button 56 of patient programmer 24. The techniqueshown in FIG. 10 is useful for modifying an open loop or modified openloop therapy system. The modified open loop therapy system may be, forexample, an open loop system that switches between therapy programgroups or adjust at least one stimulation parameter value (or othertherapy parameter) if an event metric indicates the current therapyprogram is relatively ineffective. Thus, the technique shown in FIG. 10may be used with the techniques shown in FIGS. 6A-8, in which the eventmarkers generated when patient activates event indication button 56 orprogrammer 24 otherwise receives an indication a patient event occurredis used to evaluate a therapy program or switch between therapyprograms. However, the technique shown in FIG. 9 may be usedindependently of the techniques shown in FIGS. 6A-8.

Processor 46 of patient programmer 24 receives an indication that apatient event occurred, e.g., via event indication button 56 (80).Processor 46 may generate an event marker (82), and, in some examples,record the date and time the event marker was generated (84). Upongenerating the event marker (82), processor 46 may determine whethertherapy is currently being delivered to patient 14 (110). For example,in the case of IMD 16, processor 46 may determine whether stimulationwas being delivered to patient 14 at approximately the same time patient14 activates event indication button 56 and the event marker wasgenerated. In examples in which IMD 16 operates in an open-loop,processor 46 may determine whether IMD 16 is currently in the on-cycleof stimulation or in the off-cycle during which no stimulation isdelivered to patient 14 (110).

Just as in the technique shown in FIG. 9, if therapy is not currentlybeing delivered, i.e., IMD 16 is in the off-cycle, processor 46 providesa control signal to IMD 16 or otherwise controls IMD 16 to initiatetherapy delivery (112), which restarts the therapy cycle.

If therapy is currently being delivered to patient (110), i.e., IMD 16is currently in an on-cycle of a therapy cycle, processor 46 provides acontrol signal to IMD 16 or otherwise controls IMD 16 restart theon-cycle, and, in effect, restart the therapy cycle (116). Just as inthe technique shown in FIG. 9, the event marker generated by processor46 may act as the control signal or processor 46 may generate anothercontrol signal. In this way, patient 14 may directly affect the therapycycle implemented by IMD 16 by activating event indication button 56.Furthermore, because IMD 16 maintains the same timing between anon-cycle and off-cycle, but only initiates or restarts the cycle upongeneration of the event marker by processor 46, therapy system 10remains an open loop system that provides stimulation in a regularcycle. Thus, after the on-cycle is restarted, IMD 16 continuesimplementing the normal therapy cycle.

In contrast to the technique shown in FIG. 9, however, the techniqueshown in FIG. 10 includes modifying a therapy parameter value if IMD 16is currently in an on-cycle (116). If patient 14 activates eventindication button 56 because of the occurrence of an event, and therapyis currently being delivered to patient (i.e., IMD 16 is in anon-cycle), restarting the therapy cycle and continuing to delivertherapy at the current therapy parameters may not provide sufficientlyefficacious therapy to patient 14 to address the occurrence of theevent. Thus, in addition to restarting the on-cycle, one or more therapyparameter values may be changed upon patient activation of eventindication button 56.

In the case of electrical stimulation, for example, the intensity ofstimulation may be increased. For example, the current or voltageamplitude of stimulation may be increased or the pulse rate or pulsewidth may be increased. In the case of drug delivery, for example, theconcentration or size of a drug bolus may be increased upon patientactivation of event indication button 56. However, other therapyparameter adjustments are contemplated. In some examples, if IMD 16 iscurrently in an on-cycle when patient activates event indication button56, processor 46 of patient programmer 24 may control the adjustment ofone or more therapy parameters without restarting a therapy cycle.

FIGS. 11A-11D are conceptual timing diagrams illustrating an exampletherapy cycle 118 implemented by IMD 16. As shown in FIG. 11A, eachtherapy cycle 118 includes a stimulation on-cycle 120 followed by astimulation off-cycle 122. In the example shown in FIG. 11A, therapycycle 118 repeats during the time IMD 16 is turned on and implementedinto therapy system 10 (FIG. 1). IMD 16 delivers stimulation to patient14 via electrodes 30, 31 of leads 20 during stimulation on-cycle 120,and during the stimulation off-cycle 122, no stimulation is delivered topatient 14. However, IMD 16 typically does not shut down duringstimulation off-cycle 122, but rather therapy module 32 (FIG. 2) merelystops delivering stimulation to patient 14. In some examples, a minimumlevel of stimulation is provided to patient during the stimulationoff-cycle 122, and the intensity of the stimulation increases during thestimulation on-cycle 120. Depending upon the patient disorder, it may beundesirable to completely turn stimulation off.

FIG. 11B is a timing diagram illustrating how therapy may be modifiedupon receiving an indication of a patient event, either via eventindication button 56 or based on signals from sensing module 40 (FIG. 2)that indicate a physiological parameter of patient 14. The descriptionof FIGS. 11B-11D will primarily refer to receiving an indication of apatient event from the patient via event indication button 56. Thetechniques described with respect to FIGS. 11B-11D may, however, also beapplicable to modifying therapy delivery upon receiving an eventindication that is generated based on signals from sensing module 40.

If patient 14 begins experiencing symptoms of a seizure, e.g., detectsan aura, and activates event indication button 56 during an off-cycle,as indicated by arrow 124 in the timing diagram shown in FIG. 11B,processor 46 of patient programmer 42 generates a control signal andtransmits the control signal to IMD 16, which initiates therapy on-cycle120′. On-cycle 120′ is substantially similar in duration to on-cycle120. Because on-cycle 120′ is initiated prior the end of off-cycle 126,off-cycle 126 is shorter than the normal off-cycle 122 set forth by thetherapy parameter values controlling therapy delivery by IMD 16 andtherapy cycle 118 is interrupted, as indicated by the shortened therapycycle 128 in FIG. 11B. However, because therapy cycle 118 is restartedupon the activation of button 56, the subsequent therapy cycles 118remain the same, i.e., have the duration set forth by the therapyparameter values controlling therapy delivery by IMD 16.

As FIG. 11B illustrates, patient 14 may modify the open-loop therapysystem 10 by providing input via button 56 of programmer 24 thatindicates one or more symptoms of a seizure were experienced, andtherefore, an onset of a seizure may be possible. In response toproviding the indication, therapy is provided (120′), regardless of thepoint in the therapy cycle 118 in which IMD 16 is operating. In thisway, button 56 of programmer 24 provides substantially on-demand therapyto patient 14 at a time when the therapy may be effective in preventingthe seizure or mitigating the severity or duration of the seizure.

FIG. 11C is a timing diagram illustrating another scenario, in whichpatient 14 activates event indication button 56 during an on-cycle, asindicated by arrow 130. As a result, therapy cycle 118 is restarted, andthe on-cycle 132 has a longer duration than the normal on-cycle 118.Because therapy cycle 118 is restarted during a normal on-cycle 118,another on-cycle is tacked onto the current on-cycle, resulting in alonger on-cycle 132 and a longer therapy cycle 134. However, aftercompletion of the current on-cycle 126, subsequent therapy cycles 118remain the same, at least until event indication button 56 is activatedby patient 14.

FIG. 11D is a timing diagram illustrating another scenario, in whichpatient 14 activates event indication button 56 just prior to thebeginning of on-cycle 120, as indicated by arrow 136. In this case,therapy cycle 118 is restarted, but because the initiation of thetherapy cycle 118 substantially corresponds to the previous therapycycle 118, there is no change in the therapy cycle 118 implemented byIMD 16.

In some cases, event indication button 56 of patient programmer 24 maybe inadvertently activated, e.g., when no patient event has actuallyoccurred. Patient 14 or another user may inadvertently press button 56or button 56 may accidentally be pressed when programmer 24 is in thepatient's pocket or bag. Because therapy may be adjusted in response topatient event indications received via activation of button 56, it maybe desirable to confirm the patient input via button 56. FIGS. 12A and12B are flow diagrams illustrating example techniques for confirmingpatient input indicating an occurrence of a patient event.

In FIG. 12A, processor 46 of patient programmer 24 may receive patientinput indicating the occurrence of a patient event (140), e.g., viaactivation of event indication button 56 of programmer 24. Processor 46may confirm patient input (142) prior to generating an event marker(82). As described with respect to FIGS. 6A-10, the event marker may beused to adjust therapy delivery to patient 14 or evaluate a therapyprogram or program group. Processor 46 may confirm the patient input(142) using any suitable technique. In some examples, processor 46 mayconfirm patient input (142) by validating that the patient eventoccurred. For example, processor 46 may confirm the occurrence of thepatient event based on physiological parameter values of patient 14,e.g., determined based on signals from sensing module 40 of IMD 16 (FIG.2). For example, if the patient event comprises a seizure or a symptomof a seizure, processor 46 may independently determine whether a seizurehas occurred, is occurring or is likely to occur based on EEG signalsmonitored by sensing module 40.

As shown in FIG. 12B, in other examples, processor 46 may confirmpatient input by asking patient 14 to validate the patient input wasintentionally provided. In the technique shown in FIG. 12B, afterreceiving patient input indicating the occurrence of a patient event(140), processor 46 may prompt patient 14 to confirm the patient input(144). For example, processor 46 may present a user interface screen viadisplay 58 of user interface 44 (FIG. 2) that asks patient 14 to takeanother action to confirm that the input was intentional. For example,processor 46 may prompt patient 14 to press button 56 one more time,press a particular number of buttons at the same time or in a certainorder, input a predetermined alphanumeric code, or the like.

If processor 46 receives input from patient 14 confirming that thepatient event indication was valid, processor 46 may generate an eventmarker (82). On the other hand, if processor 46 fails to receive patientinput confirming that the patient event indication was intentional,processor 46 may disregard the patient event indication input (148). Inparticular, processor 46 may not take any action to adjust therapydelivery to patient 14 based on the patient input.

FIG. 13 is a flow diagram illustrating another example technique foradjusting therapy delivery to a patient based on patient eventindications. Processor 46 may receive an indication of a patient event(80) and generate an event marker (82). As described with respect toFIGS. 6A and 6B, in some examples, processor 46 may record the date andtime the event marker was generated. In addition, processor 46 mayassociate the event marker with a therapy program or a therapy group (asshown in FIG. 13) (86) and store the event marker in memory 50 ofprogrammer 24 or a memory of another device.

Processor 46 may determine whether the indication of the patient eventis associated with an off-cycle of a therapy cycle (150), e.g., bydetermining whether the event marker was generated at substantially thesame time as the off-cycle (e.g., during or within a particular timerange, such as within five seconds off the therapy off-cycle). Asdiscussed with respect to FIGS. 11A-11D, a therapy cycle may include atleast one on-cycle in which therapy is delivered and at least oneoff-cycle in which therapy is not delivered. If processor 46 determinesthat the patient event indication is associated with a therapy off-cycle(i.e., is associated with the therapy off-cycle), processor 46 mayincrement an efficacy indication counter (152). In other examples,processor 46 may implement other techniques for counting the number oftimes a patient event indication is associated with a therapy off-cycle.

Processor 46 may determine whether the number of efficacy indicationsare greater than or equal to a threshold value (154). The thresholdvalue may be stored within memory 50 of programmer 24 or a memory ofanother device, and may indicate the threshold number of times a patientevent may occur during a therapy off-cycle in order to determine that aparticular therapy program or program group is ineffective. Thethreshold value may be determined by a clinician, e.g., based on pastpatient data or based on clinician knowledge. For example, the clinicianmay determine that if ten patient events associated with a particulartherapy program or group occurred during the therapy off-cycle, thetherapy program or group is relatively ineffective a therapy adjustmentmay be desirable.

Accordingly, if the number of efficacy indications associated with atherapy program or group is greater than or equal to the thresholdvalue, processor 46 may control the adjustment of therapy (156). Therapyto patient 14 may be adjusted by, for example, switching therapyprograms or therapy program groups or adjusting one or more therapyparameter values. If a large number of patient events are observed (asindicated by the number of patient event indications or event markersassociated with the therapy program or group) during an off-cycle of thetherapy delivery, processor 46 may adjust therapy such that the therapyoff-cycles durations are shortened or less frequent.

If processor 46 determines that the patient event indication is notassociated with a therapy off-cycle, e.g., the event marker was notgenerated during or within a predetermined time range of a therapyoff-cycle, processor 46 may wait for another indication of a patientevent (80). In some examples, processor 46 may generate an event metricto evaluate the therapy program based on the number of patient eventindications associated with the therapy program generally (rather than atherapy off-cycle), as described with respect to FIGS. 6A and 6B.

In other examples, rather than comparing the number of efficacyindications associated with a therapy off-cycle to a threshold value,processor 46 may determine whether a particular number of patient eventindications are observed during the therapy off-cycle relative to thetherapy on-cycle. Processor 46 may determine a ratio of the number ofpatient event indications associated with the therapy off-cycle to thenumber of patient event indications associated with a therapy on-cycle.If the ratio exceeds a threshold value, processor 46 may adjust therapy(156).

In some cases, a clinician may wish to evaluate whether patientprogrammer 24 including event indication button 56 that provides patient14 with some control over therapy delivery by IMD 16 is a usefulfeature. As previously described, patient 14 activation of eventindication button 56 may result in an adjustment to therapy, such as ashift between therapy programs or program groups implemented by IMD 16,a change in a therapy cycle, or a modification to at least one therapyparameter value. Patient 14 may test patient programmer 24 during atrial stage, which may be, for example, a few days, weeks, months or anyother time period that provides sufficient time to evaluate patientprogrammer 24 in view of any fluctuations in the patient's condition.The clinician may determine whether to implement patient programmer 24or another patient programmer that does not include the functionality ofevent indication button 56 (e.g., a modified patient programmer 24)based on the patient's frequency of usage of indication button 56 andfeedback indicating the efficacy of the indication button 56.

FIG. 14 is a flow diagram illustrating an example technique patientprogrammer 24 may implement during a trial stage in which patient 14evaluates patient programmer 24. Processor 46 of patient programmer 24may receive an indication of a patient event via event indication button56 (80), and if desired, generate an event marker (82), record the dateand time of the event marker (84), and associate the event marker withthe current therapy program group (86). Rather than adjusting therapy,such as by switching to another therapy program (FIGS. 6A and 6B),restarting a therapy cycle (FIGS. 9-11D) or modifying at least onetherapy parameter value, processor 46 may generate a placebo indicationto patient 14 (160) and may not implement control of IMD 16 or otherwisetake action to control therapy delivered by IMD 16. The placeboindication may be presented, e.g., via display 58 of patient programmer24, via an audible sound generated by patient programmer 24 or anothersensory cue.

The placebo indication provides feedback to patient 14 to indicate thatthe activation of event indication button 56 was received, and in somecases, may even indicate that the therapy delivered by IMD 16 wasadjusted in response to the activation of event indication button 56,although no adjustment was actually was made. If IMD 16 delivers therapyto patient 14 according to a therapy program prior to receiving thepatient event indication (80), IMD 16 may continue delivering therapy topatient 14 according to the therapy program after receiving the patientevent indication (80) and generating the event marker (82).

The clinician may not inform patient 14 that event indication button 56is merely a placebo and does not directly affect therapy delivery by IMD16. Thus, patient 14 may believe that therapy was triggered or adjustedafter event indication button 56 was activated. In some cases, receivingthe placebo indication (160) may cause the placebo effect, in whichpatient 14 feels therapeutic effects, although IMD 16 functionality wasnot changed. During this trial stage in which patient input indicating apatient event occurred does not adjust therapy delivery, IMD 16 may beset to deliver stimulation at regular intervals, substantiallycontinuously or deliver no stimulation at all. If a clinician evaluateswhether patient 14 needs therapy in order to control a condition, suchas seizures, IMD 16 may be configured to deliver no stimulation duringthe trial stage.

Patient programmer 24 may prompt patient 14 to input information intopatient programmer 14 after activating event indication button 56. Inthis way, processor 46 may receive patient feedback relating to theoccurrence of the patient event (162). For example, user interface 78 ofpatient programmer 24 may provide text boxes into which patient 14 maymanually input data relating to the duration, severity, and/or type ofseizure, and the effectiveness of the therapy upon activating eventindication button 56. Alternatively, user interface 78 may providepull-down menus by which patient 14 may select from preset options ormultiple choice questions that patient 14 may answer to provide input.Processor 46 may associate the patient feedback with the event marker(164), and store the information (patient feedback and event marker)within memory 50 of patient programmer 24 or control telemetry module 48(FIG. 3) to transmit the information to memory 36 of IMD 16 (FIG. 2) ora memory of another device.

After the trial stage, patient 14 may return to the clinician's officeand the clinician may review information relating to the event markersand the patient feedback, which may be stored within patient programmer24 and/or IMD 16. For example, the clinician may download data frompatient programmer 24 and/or IMD 16. The information may include thenumber of event markers, the date and time the event markers weregenerated, and the patient's feedback associated with the event markers.The clinician may evaluate various aspects of the trial stage. Forexample, if IMD 16 implemented more than one therapy program during thetrial stage, the clinician may evaluate the efficacy of each therapyprogram based on the event markers associated with the therapy programs.

As another example, the clinician may evaluate whether patient 14believed event indication button 56 had any effect on therapy based onthe patient feedback. If the patient feedback indicated that activatingevent indication button 56 provided efficacious therapy when eventindication button 56 merely resulted in the placebo indication, theclinician may discern that patient 14 does not need patient programmer24 that includes a functional event indication button 56. On the otherhand, if the feedback from patient 14 indicated that activating eventindication button 56 did not provide efficacious therapy, the clinicianmay wish to provide patient 14 with a patient programmer 24 including afunctioning event indication button 56 that allows patient 14 to bettercontrol therapy delivery by IMD 16 or further test whether eventindication button 56 is a useful therapy tool for patient 14.

As previously indicated, in some examples, patient 14 may input eventinformation related to the patient event into patient programmer 24. Theevent information may include an efficacy of therapy delivery by themedical device, a type of patient event, a duration of the patientevent, a severity of the patient event, a type of drug taken prior tothe patient event, a drug dosage taken prior to the patient event or anactivity engaged in by the patient prior to the patient event. Patientprogrammer 24 and/or clinician programmer 22 may display the eventinformation, which may then be used evaluate the therapy delivery topatient 14 or the patient's condition.

In some examples, the generation of the event marker may result in thecreation of a new data file stored in the event data 60 section ofmemory 50 (FIG. 3) of patient programmer 24. The data file may beeditable by a user, including patient 14 or a clinician. For example,the data file may include data fields that store information about thepatient's therapy or the patient event. As examples, the data file mayinclude information about the type or severity of a seizure, theduration of the seizure, the efficacy of therapy, the drug and/or drugdosage being taken prior to or after the seizure, and the like. Userinput mechanism 54 (FIG. 3) of patient programmer 24 may allow patient14 to enter the relevant information at any time following thegeneration of the event marker. For example, in the case of an eventrelated to a seizure, patient 14 may enter information relating to theseizure following recovery from the seizure event, and may edit theinformation during some time period following the initial entry of thedata.

FIG. 15 is a flow diagram illustrating an example method for storingpatient event information on patient programmer 24. Patient 14 maydetect the occurrence of an event related to a patient condition. In thecase of a seizure, for example, patient 14 may sense an aura, which maybe, in some cases, a precursor to a tonic-clonic seizure. An aura may bea simple partial seizure, and may be indicated by a wide range ofsymptoms including, for example, lightheadedness, dizziness, unusualemotions, altered vision and hearing, and the like. When patient 14perceives an aura, patient 14 may provide an indication to patientprogrammer 24 by, for example, activating event indication button 56(170). Processor 46 of patient programmer 24 is coupled to eventindication button 56, and, therefore, receives the indication of theevent (170), and generates an event marker (172). As previouslydescribed, the event marker may be a flag, value or other signal.Processor 46 may record the date and time of the event marker withinevent data 60 of memory 50 of patient programmer 24 (174), which may be,for example, the date and time processor 46 generated the event marker.

The resolution of the time and date stamp of the event marker may be onthe order of seconds, for example, or may be less accurate, such as onthe order of five minute increments, fifteen minute increments, or evenhour increments. The time accuracy may be programmed by the clinician,or may be preprogrammed into patient programmer 24. Recording the timeand date that each event marker was generated by processor 46 mayindicate each time patient 14 activated the event indication button 56.A clinician may later reference the event markers to determine anypatterns or trends in the occurrence of patient events. For example,events occurring repeatedly at approximately the same time of day mayindicate an emotional triggering of the event, such as stress at work orschool.

Generation of an event marker may also cause patient programmer 24 toquery IMD 16 and record the therapy program or group of programs beingimplemented by IMD 16 at the time processor 40 generated the eventmarker. Alternatively, patient programmer 24 may transmit the eventmarker to IMD 16, which may associate the event marker with a currenttherapy program or group. Depending upon the type of IMD 16 or the modeof operation of IMD 16, in some cases, processor 46 may associate theevent marker with a single therapy program, rather than a program group,which may include one or more therapy programs. Thus, while programgroups are primarily referred to throughout the description of FIG. 15,in other examples, processor 46 may associate the event marker with atherapy program.

As previously described, processor 46 may interrogate IMD 16 todetermine which program group IMD 16 is currently delivering therapy inaccordance with, or processor 46 may track the current program groupwithin therapy programs 62 portion of memory 50. Patient 14 may notactivate event indication button 56 as soon as the patient event occurs.For example, if a patient 14 is struck with a seizure, patient 14 maynot be able to activate event indication button 56 until after patient14 recovers from the seizure, which may be well after the occurrence ofthe seizure. For example, depending upon the duration and severity ofthe seizure, recovery may take minutes or even hours. Thus, processor 46may associate the event marker with the most recently implementedtherapy program or the currently implemented therapy program.Alternatively, patient programmer 24 may provide patient 14 with theopportunity to modify the date and time of the event marker. If patient14 knew, for example, that the event occurred at least two hours beforepatient 14 actually activated event indication button 56, patient 14 maymodify the time of the event marker by at least two hours via user inputmechanism 54 (FIG. 3).

As described briefly above, in some examples in which IMD 16 providestherapy in accordance with a therapy cycle, the therapy cycle may bereset when patient 14 activates event indication button 56. In this way,patient 14 may directly affect the therapy cycle implemented by IMD 16by activating event indication button 56. In some cases, resetting thetherapy cycle implemented by IMD 16 may help prevent the onset of theseizure because therapy is essentially provided on demand, i.e., inresponse to the activation of event indication button 56. For example,if patient 14 senses an aura and activates event indication button 56,the delivery of therapy resulting from the resetting of the therapycycle may prevent the aura from developing into a more severe seizure,such as a tonic-clonic seizure, or may lessen the duration or severityof the tonic-clonic seizure.

Regardless of whether processor 46 initiates adjustment of therapy inresponse to receiving an indication of the event via event indicationbutton 56, patient 14 may enter information regarding the event and theefficacy of treatment (176) into programmer 24 at any time following thegeneration of the event marker. For example, if the aura does notdevelop into a more severe seizure, such as a tonic-clonic seizure,patient 14 may enter the data soon after activating event indicationbutton 56 and the subsequent generation of the event marker. If,however, the aura does develop into a more severe seizure, such as atonic-clonic seizure, patient 14 may enter the information at any timeafter recovering from the seizure.

Information may be input via user input mechanism 54 of patientprogrammer 24 as described in detail with reference to FIG. 3. Patient14 may input the event information into patient programmer 24 by anysuitable technique. As examples, patient 14 may select a predeterminedentry from a list presented by a user interface of patient programmer24, selecting an entry from a drop-down list presented by the userinterface, selecting an icon presented by the user interface thatrepresents the desired information, inputting text into patientprogrammer 24, and the like. An example of a user interface is describedin further detail with reference to FIGS. 17A-17E.

The information that is inputted by patient 14 may include, for example,the seizure type or severity of the patient event. Seizure types may becategorized by the extent to which they affect the brain, the affect ona patient's consciousness, and the behavioral effects. For example, apartial seizure may only affect a localized area of brain 12 (FIG. 1),while a generalized seizure may affect both hemispheres of brain 12.Each of these major categories may be further broken up into a number ofsub-categories such as, for example, simple partial seizures, complexpartial seizures, absence seizures, tonic-clonic seizures, and the like.When a clinician programs patient programmer 24, the clinician maypopulate a list with the types of seizures patient 14 is most likely toexperience or all available seizure types. The list may include aplurality of seizure types, such as less than five, five, or more thanfive. The clinician may also assign nicknames to each type of seizureaccording to terms with which patient 14 may be more familiar. Forexample, patient 14 may identify a tonic-clonic seizure as a “SevereSeizure” and an absence seizure as a “Short-term Seizure.” Thus, theclinician and patient 14 may each use familiar language to identify theseizures. Further, in some examples, the list may include an editableoption that allows a patient to enter a seizure type that is nototherwise included in the list.

Another exemplary type of event information input by patient 14 intopatient programmer 24 may include the seizure duration. The seizureduration may be entered as any suitable time duration, such as, forexample, five minute increments, or may be as accurate as patient 14 isable to determine. In some examples, patient programmer 24 may present alist including predetermined durations of time in order to provide auniform time scheme. Seizure duration may be input via alphanumericbuttons, or may be selected from a dropdown list, a checkbox or thelike.

Yet another example of information that may be inputted into patientprogrammer 24 by patient 14 may include an efficacy of the therapy.Efficacy of the therapy may refer to the patient's subjective rating ofthe general efficacy of therapy delivered via IMD 16. For example,patient 14 may assign an efficacy rating to the therapy program orprogram group implemented by IMD 16 at the time patient 14 perceived thepatient event. In general, patient 14 may provide information thatindicates whether the therapy delivered by IMD 16 was effective inprevent the patient event, reducing the severity or of the patientevent, reducing the frequency of patient events, or reducing anyresidual effects of the patient event. In examples in which processor 46of patient programmer 24 initiates the adjustment of one or more therapyparameter values or therapy cycles in response to the activation ofevent indication button 56, patient 14 may input information regardingthe efficacy of the adjustments to therapy. Efficacy information may beespecially useful in evaluating therapy system 10 in examples in whichactivating event indication button 56 resets the therapy cycleadministered to patient 14 or initiates a change in the therapy programimplemented by IMD 16.

In some examples, therapy efficacy information may not be immediatelyavailable. For example, patient 14 may not be able to discern betweenefficacious and non-efficacious therapy for a period of time afterimplantation of IMD 16 and commencement of therapy. In these examples,efficacy of the therapy may be determined by patient 14 after aplurality of patient events have occurred or after a sufficient timeperiod of therapy delivery has passed.

In some examples, patient 14 may determine the efficacy of therapy bycomparing the duration, severity or type of seizure that occurred afterthe adjustment to therapy or implementation of therapy system 10 to abaseline condition. The baseline condition may be, for example, thepatient's condition prior to implementation of therapy system 10 orprior to the adjustment of therapy, if any, that was made in response toactivating event indication button 56 (e.g., at substantially the sametime the event marker was generated). In other examples, patient 14 maydetermine the efficacy of therapy based on the absence of a seizureafter perception of an aura or a relatively less severe seizure (e.g.,compared to prior seizures experienced by patient 14). Therapy efficacyinformation may be entered according to a numeric scale, for example,1-5, where 1 indicates no seizure (a very efficacious therapy) and 5indicates no change (non-efficacious therapy) or any other techniquethat indicates the relative effectiveness of therapy.

In some examples, patient programmer 24 may provide patient 14 with auser interface that permits patient 14 to input manually notes relatingto event, and the notes may be associated with the event marker andstored within event information 50 portion of memory 42 (FIG. 3). Forexample, patient 14 may enter notes indicating an activity patient 14was engaging in prior to perceiving an aura (e.g., exercise, eating,stressful situation, etc.), diet information, further description of theseverity or type of the seizure, if one occurred, the effects of theseizure, or any other information patient 14 deems applicable to histherapy or condition.

As another example, patient 14 may enter information relating to thetype or dosage of a drug or other pharmaceutical agent taken prior tothe event or after a seizure occurred. Patient 14 may also inputinformation specifying the time at which the drug or otherpharmaceutical agent was ingested or otherwise received by patient 14.For example, patient 14 may take one anti-seizure drug in regular dosesat consistent time intervals, and after a tonic-clonic seizure, patient14 may ingest a more potent anti-seizure medication to prevent anyadditional seizures from occurring for an amount of time after thetonic-clonic seizure. In other examples, medication information may bestored in memory 36 of 1 MB 16 or memory 50 of patient programmer 24.Medication type and dosage may further help a clinician evaluate theefficacy of the currently prescribed therapy and determine if anychanges to therapy are necessary and, if so, determine the nature of thechanges.

After receiving event information (176), processor 46 of patientprogrammer 24 may associate the received event information with thecorresponding event marker (178) and store the event marker and receivedinformation in event data 60 (180). Alternatively, processor 46 maytransmit the information to IMD 16, which may store the data withinmemory 36. In some examples, processor 46 of patient programmer 24 maynot immediately receive patient event information after the generationof the event marker. In those cases, processor 46 may associate theinformation received from patient 14 with the most recently generatedevent marker. In some examples, patient programmer 24 may display all ora portion of the event information associated with each of the eventmarkers to patient 14, such as upon the request of patient 14.Displaying the event information to patient 14 may allow patient 14 tomore closely monitor his or her therapy and condition.

In some examples, patient programmer 24 (or IMD 16) may store the eventmarker and event information until the subsequent clinic visit ofpatient 14. The clinician may review the event information and eventmarkers to monitor the response of patient 14 to therapy, and, ifnecessary, generate a new treatment plan for patient 14. Uponinterrogation by a computing device, such as clinician programmer 22,processor 46 of patient programmer 24 may control telemetry module 48(FIG. 3) to transmit the event information and event marker to thecomputing device (182). Alternatively, processor 46 of patientprogrammer 24 may initiate the transmittal of the event information andassociated event marker.

As discussed in more detail below, a clinician may manipulate and/orselect areas of interest in the event information and clinicianprogrammer 22 or another computing device may generate various displaysof information, such as tables, bar graphs, Venn diagrams, and the likethat present the event information in a more meaningful way. Graphicaldisplays of information may reveal trends or other information useful tothe clinician in treating patient 14. For example, event information maybe viewed over a time period of multiple months, and a clinician mayview the data to determine if a patient's response to a particulartherapy parameter set is diminishing, or if the patient's response isunchanging or even improving.

FIG. 16 is a flow diagram illustrating an example technique that acomputing device, such as clinician programmer 22 or patient programmer24, may employ to display event information received from patient 14and/or physiological parameter sensors. While FIG. 16 is primarilydescribed with reference to clinician programmer 22, in other examples,another computing device such as patient programmer 24 may perform anypart of the technique shown in FIG. 16. Clinician programmer 22 maycouple to patient programmer 24 through their respective telemetrymodules 48 (190). Clinician programmer 22 may send a query or otherwiseinterrogate patient programmer 24 to retrieve event information storedin memory 50 of patient programmer 24 (192). In response to receivingthe query, patient programmer 24 may transfer the event information(including the event marker) to clinician programmer 22.

After receiving the patient event information, processor 46 of clinicianprogrammer 22 may format and display the event information (194). Theevent information may be displayed in a variety of display formats,including, for example, tables, lists, graphs, charts, and the like.Memory 50 of clinician programmer 22 may store software that causesprocessor 46 to generate different types of displays. In some examples,the clinician programmer 22 may optionally prompt the clinician or otheruser to select one or more types of patient event information to display(e.g., duration and severity of seizures or the event markers andcorresponding time stamps), as well as the type of display format fordisplaying the event information. For example, the clinician may wish toview the event information as a bar graph showing number of activationsof event indication button 56 per week for a three month period. Asanother example, the clinician may wish to view a table of all the eventinformation provided by patient 14 organized based on the respectiveevent markers.

FIGS. 17A-17E illustrate example user interfaces that may be presentedby patient programmer 24 to allow a patient 14 to enter eventinformation. Patient programmer 24 includes user input mechanisms 54a-54 f (collectively “user input mechanisms 54”), event indicationbutton 56, and display 58. Patient 14 may interact with user inputmechanisms 54 to input event information into patient programmer 24,and, in some cases, control aspects of therapy delivered by IMD 16within the limits programmed by a clinician. User input mechanismsinclude buttons 54 a and 54 b, which may be used to increase or decreasethe therapy intensity, if allowed, and may perform other functions, asallowed by the operating software 64 (FIG. 3). An intensity of therapymay be modified by, for example, modifying a therapy parameter value,such as the current or voltage amplitude of stimulation signals, thefrequency of stimulation signals, the shape of a stimulation signal orthe electrode combination used to deliver the stimulation signal.

Multi-directional controller 54 f may allow a user to navigate throughmenus displayed by display 58, and may include a button 54 g that isactuated when the center of multi-directional controller 54 f ispressed. Event indication button 56 is used to perform any of thefunctions ascribed to it herein, including, for example, generating anevent marker and/or resetting or modifying a therapy cycle.

Display 58 may display graphical user interface screens that provide aninterface for patient 14 to enter event information. While display 58shows five individual screens in FIGS. 17A-17E, in other examples, thedescribed screens may be displayed on a single screen divided intomultiple sections, may be combined in any of other combinations ofdisplay screens, or may be omitted. The five screens shown in theillustrated examples include time stamp screen 202 (FIG. 17A), seizuretype and severity screen 206 (FIG. 17B), duration screen 212 (FIG. 17C),notes screen 216 (FIG. 17D), and therapy efficacy screen 218 (FIG. 17E).Each screen presents patient 14 with event information associated withan event marker or allows patient 14 to enter event information.

Time stamp screen 202, illustrated in FIG. 17A, shows the time stamp ofan event marker. In some examples, the patient 14 may change the timestamp displayed by selecting button 204 a or 204 b (either via a touchscreen interface, or by controlling a cursor via user input mechanisms54). Patient 14 may review (on screens such as those illustrated inFIGS. 17B-17E) event information associated with other event markers bychanging the currently displayed time stamp. By selecting a stored timestamp, patient 14 is essentially selecting the event marker that wasgenerated at the time reflected in the time stamp or otherwiseassociated with the time stamp (e.g., in some examples, patient 14 maymodify the time stamp of an event marker). The other user interfacescreens 20, 212, 216, and 218 may display the respective informationassociated with the selected time stamp. In other examples, the timestamp may simply display the time stamp associated with the most recentactivation of event indication button 56 and programmer 24 may notprovide patient 14 with an option for reviewing event informationassociated with other event markers.

FIG. 17B shows seizure type and severity screen 206, which allowspatient 14 to input information relating to the type of seizureexperienced (if any) and the severity of the seizure. As describedabove, the clinician may assign nicknames to different seizure typesthat correspond to the name with which patient 14 refers to the seizure.In the illustrated example, “Severe” may refer to a tonic-clonic seizureand “Minor” may refer to an absence seizure. Patient 14 may select thetype of seizure using multi-directional controller 54 f or any othersuitable element of user input mechanisms 54. Selection of a respectiveseizure type may be indicated by a selected box 210. In some examples,selecting “other” may prompt patient 14 to enter an alphanumericdescription of the seizure type. In other examples, the seizure type maybe selected from a dropdown menu (similar to the menu shown for durationscreen 212), selected by an icon, and the like.

Patient 14 or another user may also input the severity of the seizure inseverity subsection 208. The severity may be selected from a numericlist, as shown in FIG. 17B, where a rating of “1” represents leastsevere and a rating of “5” represents most severe, for example. In otherexamples, the severity may be selected from a textual list, or may beeditable by patient 14. The severity may be correlated with the type ofseizure indicated by the user. For example, a level 5 “Minor” seizuremay be viewed by a clinician as less severe than a level 1 “Severe”seizure.

In some examples, however, the severity of the patient's seizure may bedetected automatically based on values of one or more monitoredphysiological parameters of patient 14, such as an EEG signal or an ECGsignal. As previously described, IMD 16 or another sensing device maymonitor one or more physiological parameters of patient 14. The severityof the seizure may be determined based on, for example, the amplitude ofthe EEG signal waveform. Processor 46 of programmer 24 or a processor ofanother device (e.g., the sensing device or IMD 16) may determine theseverity of the seizure and automatically record the severity withinevent data 60 of memory 50 of programmer 24. Severity may be categorizedin terms of a graduated scale (e.g., a numerical scale) or anothersuitable scale. Alternatively, processor 46 may merely record the EEGsignal and clinician or another computing device may determine theseverity of the patient's seizure, if any, at the time the event markerwas generated.

As illustrated in FIG. 17C, duration screen 212 allows a user, such aspatient 14, to enter the duration of the seizure associated with thetime stamp shown in screen 202 (i.e., a particular event marker). Insome examples, the duration may initially be determined by processor 46.For example, patient 14 may activate event indication button 56 a firsttime when the patient event is sensed and a second time after patient 14perceives the patient event as being complete. The time period betweenthe first press of button 56 and second press of button 56 may bedetermined to be the duration of the event. In some examples, theduration may be edited at a later time by patient 14 or another user. Inthe illustrated example, the duration may be selected from dropdown menu214. The dropdown menu may display durations in any desired increment,such as, for example, one minute, five minute or fifteen minuteincrements. In other examples, the seizure duration may be enterednumerically, either through the use of an alphanumeric keypad, a touchscreen, or a menu-driven interface.

Notes section 216, shown in FIG. 17D, allows a user, such as patient 14,to enter any other notes deemed applicable to the therapy, event, orcondition of patient 14. Information entered in the notes section 216may include information regarding any of the other sections, such asseizure type and severity or duration, or may include notes about thecurrent medication and dosage being taken by patient 14. For example,patient 14 may input notes regarding an activity being performed at thetime of the event, a particular drug or drug dosage taken prior to orafter the event, and the like.

As another example, illustrated in FIG. 17E, patient programmer 24 maypresent a therapy efficacy screen 218 that enables patient 14 to inputinformation regarding the efficacy of therapy prior to, during or afterthe generation of the event marker. The therapy efficacy may relate tothe duration, severity or type of seizure experienced by patient 14. Forexample, patient 14 may associate a particular sensed aura with acertain type or severity of seizure. If, after activating eventindication button 56 and resetting the therapy cycle, the predictedseizure does not occur, patient 14 may infer that the therapy wasefficacious. However, if the predicted seizure still occurs, patient 14may infer that the therapy was not efficacious.

Therapy efficacy screen 218 may include, for example, one or morequestions regarding the efficacy of therapy, which patient 14 may answerby, for example, selecting a box 220. Questions posed via therapyefficacy screen 218 may include, for example: “Was the therapyeffective?” “Did the anticipated event occur?” “Was therapy as effectiveas it was X days ago?” In other examples, a numerical scale or anothertype of graduated scale for assessing relative efficacy may be presentedto patient 14 or patient 14 may provide another input indicative ofefficacy.

Event information relating to the efficacy of therapy may be especiallyuseful for evaluating therapy system 10 and determining the impact on aspecific patient's therapy. While automatically detected physiologicalparameters are useful for evaluating therapy system 10, the subjectivefeedback from patient 14 may provide information not otherwiseobtainable via the physiological parameter values. The clinician mayconsider the subjective feedback of patient 14 to be a valuable factorwhen determining whether to adjust the treatment plan for patient 14 ormaintain the current plan, as well as for evaluating the condition ofpatient 14.

Efficacy of therapy may be a useful type of event information whenprocessor 46 is configured to control IMD 16 (e.g., by generating acontrol signal that causes IMD 16 to perform some action) to adjust ormodify therapy in response to receiving an indication of the occurrenceof the event. As previously described, the therapy adjustments mayinclude resetting a therapy cycle of stimulation or drug delivery,adjusting a therapy parameter value, such as increasing a concentrationor size of a drug bolus or increasing intensity of stimulation (e.g.,via increasing a current or voltage amplitude or signal frequency), orswitching to another therapy program or group. The clinician mayevaluate event information received from processor 46 of patientprogrammer 24, and, in some cases, other sources, such as IMD 16 or asensing device, to determine whether a therapy adjustment occurred inresponse to the patient's activation of event indication button 56.Thus, the clinician may evaluate the impact the therapy adjustment ormodification had on patient 14.

Other sections or screens that may be presented by patient programmer 24are also contemplated. For example, patient programmer 24 may present adrug entry screen that allows a patient 14 to enter drug information,such as the drug type and dose taken prior to the event. The drug entryscreen may also allow patient 14 to enter the time when the drug wastaken, or when a course of drugs began and ended. The drug informationmay be selected from, for example, a dropdown list, a selectable box, ora text entry. The drug entry screen may also allow patient 14 to enterother drugs taken after an event, such as a more potent anti-seizuremedication taken to prevent more seizures for a time period after theinitial event. In some examples, a clinician assigns shorter,recognizable names for the respective drugs taken by patient 14 toassist patient 14 from identifying and selecting the drug from adropdown list or the like.

In each of the examples described above, certain techniques described asbeing performed by processor 46 of patient programmer 24 may beperformed by a processor of another computing device, such as clinicianprogrammer 22 or by a clinician. For example, in FIG. 15, a clinician ora processor of another computing device may associate event markers witha therapy program or therapy program group, e.g., based on the date andtime the event marker was generated. Furthermore, each of the featuresdescribed herein may be performed via hardware, software, firmware, orany combination thereof.

Various examples have been described. These and other examples arewithin the scope of the disclosure. For example, while the examplesdescribed herein are primarily directed toward therapy system 10 thatincludes an implanted medical device to deliver DBS, the disclosure isnot so limiting. In other examples, for example, therapy system 10 mayinclude an external DBS device, an implanted or external electricalstimulator configured to deliver therapy to treat other patientconditions, a fluid delivery device configured to deliver pharmaceuticalagents, insulin, pain relieving agents, gene therapy agents, or the liketo patient 14, one or more microstimulators or other therapy devices.

The systems and methods described herein are also useful with therapysystems that provide an electrical stimulator, fluid (e.g., drug)delivery device or another therapy device that provides pain mitigation,peripheral neuropathy or post-operative pain mitigation, pelvic nervestimulation, ilioinguinal nerve stimulation, intercostal nervestimulation, hypogastric nerve stimulation, gastric stimulation for thetreatment of gastric mobility disorders and obesity, muscle stimulation(e.g., functional electrical stimulation (FES) of muscles), formitigation of other peripheral and localized pain (e.g., leg pain orback pain), or sacral, pudendal or other pelvic nerve stimulation toinfluence the behavior of the relevant structures, such as the bladder,sphincter and pelvic floor muscles. For example, the systems and methodsdescribed herein may also be useful with spinal cord stimulation,gastric stimulation, pelvic floor stimulation, peripheral nervestimulation, deep brain stimulation, and so forth.

In addition, while the examples described herein are primarily directedtoward receiving a patient event that is related to a seizure, in otherexamples, a patient programmer may include an event indication buttonthat generates a log of patient events related to other patientconditions and the event indication button may be used to adjust therapythat controls patient conditions other than seizures. For example, apatient may activate the event indication button to indicate theoccurrence of a headache (e.g., migraine headache, cluster headache,tension headache, cervicogenic headache or occipital neuralgia), whichmay be useful if the patient is afflicted with chronic pain ormigraines.

As another example, a patient may activate event indication button 56 toindicate the occurrence of a patient event related to a psychiatricdisorder, which may include a symptom or a mood state related to apsychiatric disorder. Psychiatric disorders may include, for example,major depressive disorder (MDD), bipolar disorder, anxiety disorders,post-traumatic stress disorder, dysthymic disorder, andobsessive-compulsive disorder (OCD). For example, a patient may activatethe event indication button to indicate the occurrence of a compulsionor an obsessive thought, which may be useful if the patient is afflictedwith obsessive compulsive disorder.

As another example, a patient may activate the event indication buttonto indicate the occurrence of a depressive event, which may be useful ifthe patient is afflicted with major depressive disorder, anxietydisorder, bipolar disorder, or another psychological disorder. A patientalso may activate the event indication button to indicate the occurrenceof a depression event, which may be useful if the patient is afflictedwith major depressive disorder or another psychiatric disorder. Adepression event may include a symptom of depression, such as fatigue,anhedonia, depressed mood, loss of energy, diminished ability to thinkor concentrate, indecisiveness, or recurrent thoughts of death orsuicidal ideation, insomnia or hypersomnia. As an example, the patientsymptoms may be defined by the Diagnostic and Statistical Manual ofMental Disorders (DSM-IV), which is a book, published by the AmericanPsychiatric Association, which defines criteria used to diagnose variousmental disorders, including depression.

As another example, a patient may activate the event indication buttonto indicate the occurrence of a manic event (or episode), which may beuseful if the patient is afflicted with bipolar disorder.

In other examples, a patient afflicted with schizophrenia may provideinput to indicate the occurrence of auditory or visual hallucinations(e.g., hearing voices or seeing images that do not exist outside of thepatient's mind). Examples of manic events include inflated self-esteemor grandiosity and a decreased need for sleep. Patients afflicted withphysical or psychological dependency (i.e., addiction), e.g., to a drug,alcohol, eating, gambling, or other activities or substances, mayprovide patient input to indicate the occurrence of withdrawal symptomsor cravings.

With respect to patients afflicted with urinary or fecal incontinence,the patient event indications may indicate the occurrence of a urinaryor fecal voiding event or an urge to void felt by the patient. Forexample, the patient may provide input indicating the occurrence of theurinary or fecal voiding event or the voiding event may automatically bedetected, e.g., with the aid of sensors. The sensors may be carriedexternal to the patient, e.g., included within an undergarment worn bythe patient as described in U.S. patent application Ser. No. 11/414,626,which was filed on Apr. 28, 2006 and is entitled, “EXTERNAL VOIDINGSENSOR SYSTEM,” which is incorporated herein by reference in itsentirety. In other examples, the sensors may be implanted within thepatient and sense physiological parameters associated with the voiding,such as electrical activity of the pelvic floor muscles, movement offluid through the patient's body, and the like.

As another example, a patient may activate the event indication buttonto indicate the occurrence of a tremor episode or another symptom of amovement disorder, such as rigidity, bradykinesia, rhythmichyperkinesia, nonrhythmic hyperkinesia, akinesia, which may be useful ifthe patient is afflicted with a movement disorder (e.g., Parkinson'sdisease). Use of a patient programmer including an event indicationbutton may also be useful with other patient events and conditions.

In each of the other examples of event indication buttons describedabove, patient programmer 24 may generate a log of the date and time ofevent markers, as well as any related physiological parameter data ifthe therapy system includes a sensor to gather the information. Thepatient programmer 24 may also prompt the patient to enter data relatingto the occurrence of the symptom, such as, but not limited to, theseverity of the symptom, duration, efficacy of therapy, and so forth, asdescribed in commonly-assigned U.S. patent application Ser. No. ______to Kovach et al., entitled, “PATIENT EVENT INFORMATION” (attorney docketno. 1023-737US01/P0030324.01), which is incorporated herein by referencein its entirety. In addition or alternatively, patient programmer 24 mayassociate the event marker with a therapy program or program group inorder to evaluate the therapy programs or program groups, and, ifnecessary, instruct the medical device to switch to another therapyprogram or program group. Furthermore, activation of the eventindication button, regardless of the symptom or patient condition, maycause therapy delivery to be initiated or adjusted (e.g., restart thetherapy cycle).

The disclosure also contemplates computer-readable media comprisinginstructions to cause a processor to perform any of the functionsdescribed herein. The computer-readable media may take the form of anyvolatile, non-volatile, magnetic, optical, or electrical media, such asa RAM, ROM, NVRAM, EEPROM, flash memory, or any other digital media. Aprogrammer, such as clinician programmer 22 or patient programmer 24,may also contain a more portable removable memory type to enable easydata transfer or offline data analysis.

Various embodiments of the described invention may be implemented usingone or more processors that are realized by one or more microprocessors,ASIC, FPGA, or other equivalent integrated or discrete logic circuitry,alone or in any combination. In some cases, the functions attributed tothe one or more processors described herein may be embodied as software,firmware, hardware or any combination thereof.

Many examples of the disclosure have been described. Variousmodifications may be made without departing from the scope of theclaims. These and other examples are within the scope of the followingclaims.

1-20. (canceled)
 21. A method comprising: receiving, with one or more processors, an indication of an occurrence of a patient event related to a condition of the patient; generating, with the one or more processors, an event marker based on the indication; and adjusting, with the one or more processors, therapy delivered by a medical device to the patient, wherein the medical device delivers therapy according to a therapy cycle comprising an on-cycle during which therapy is delivered to the patient and an off-cycle during which therapy is not delivered to the patient, and wherein adjusting therapy comprises: determining, with the one or more processors, whether the medical device is in the off-cycle or the on-cycle of the therapy cycle implemented by the medical device at a time based on the generation of the event marker; with the one or more processors, initiating the on-cycle if the medical device is in the off-cycle at the time, thereby shortening a duration of the off-cycle of the therapy cycle implemented by the medical device at the time; and with the one or more processors, restarting the on-cycle if the medical device is in the on-cycle at the time, thereby elongating a duration of the on-cycle of the therapy cycle implemented by the medical device at the time.
 22. The method of claim 21, wherein adjusting therapy comprises generating a signal to control the medical device to adjust the therapy delivered to the patient.
 23. The method of claim 21, wherein the patient condition comprises at least one of a seizure disorder, a psychiatric disorder, urinary incontinence, fecal incontinence, chronic headaches or a movement disorder.
 24. The method of claim 21, wherein the medical device is configured to deliver the therapy to the patient according to at least one therapy program, the method further comprising: associating, with the one or more processors, the event marker with the at least one therapy program; and determining, with the one or more processors, an event metric for the at least one therapy program based on the event marker.
 25. The method of claim 24, wherein the event metric comprises at least one of a total number of event markers associated with the at least one therapy program, a number of event markers per unit of time or a change from a baseline condition of the patient.
 26. The method of claim 21, further comprising: receiving, with the one or more processors, event information relating to the patient event from at least one of the patient or a sensing module; associating, with the one or more processors, the event information with the event marker; and with the one or more processors, storing the event information within a memory.
 27. The method of claim 26, wherein the event information comprises at least one of an efficacy of therapy delivery by the medical device, a type of patient event, a duration of the patient event, a severity of the patient event, a type of drug taken prior to the patient event, a drug dosage taken prior to the patient event or an activity engaged in by the patient prior to the patient event.
 28. The method of claim 21, wherein, during the on-cycle, the medical device delivers the therapy to the patient according to at least one therapy program that defines a therapy parameter value, and adjusting therapy further comprises modifying the therapy parameter value.
 29. The method of claim 21, wherein, during the on-cycle, the medical device delivers the therapy to the patient according to a first therapy program and adjusting therapy further comprises selecting, with the one or more processors, a second therapy program for the medical device.
 30. The method of claim 21, wherein the time is a time at which the event marker is generated.
 31. The method of claim 21, wherein receiving the indication of the occurrence of the patient event comprises receiving the indication from the patient.
 32. The method of claim 21, wherein receiving the indication of the occurrence of the patient event comprises receiving the indication from a sensing module.
 33. A system comprising: a medical device configured to deliver therapy to a patient according to a therapy cycle comprising an on-cycle during which therapy is delivered to the patient and an off-cycle during which therapy is not delivered to the patient; and one or more processors configured to receive input indicating an occurrence of a patient event, wherein the patient event is related to a condition of the patient, generate an event marker based on the indication, determine whether the medical device is in the off-cycle or the on-cycle of the therapy cycle implemented by the medical device at a time based on the generation of the event marker, initiate the on-cycle if the medical device is in the off-cycle at the time, thereby shortening a duration of the off-cycle of the therapy cycle implemented by the medical device at the time, and restart the on-cycle if the medical device is in the on-cycle at the time, thereby elongating a duration of the on-cycle of the therapy cycle implemented by the medical device at the time.
 34. The system of claim 33, wherein the one or more processors are configured to receive the input from the patient.
 35. The system of claim 34, further comprising a medical device programmer comprising an event indication input mechanism, wherein the one or more processors are configured to receive the input from the patient via the event indication input mechanism.
 36. The system of claim 33, further comprising a sensing module configured to one or more of collect, measure, or calculate physiological parameter data for the patient, wherein the one or more processors are configured to receive the input from the sensing module.
 37. The system of claim 33, wherein the medical device delivers the therapy to the patient according to at least one therapy program, and the one or more processors are configured to associate the event marker with the at least one therapy program and determine an event metric for the at least one therapy program based on the event marker.
 38. The system of claim 37, wherein the event metric comprises at least one of a total number of event markers associated with the at least one therapy program, a number of event markers per unit of time or a change from a baseline condition of the patient.
 39. The system of claim 33, further comprising a user interface and a memory, wherein the one or more processors are configured to receive event information relating to the condition of the patient from at least one of the patient via the user interface or a sensing module, associate the event marker with the event information, and store the event information and event marker in the memory.
 40. The system of claim 39, wherein the event information comprises at least one of an efficacy of therapy delivery by the medical device, a type of patient event, a duration of the patient event, a severity of the patient event, a type of drug taken prior to the patient event, a drug dosage taken prior to the patient event or an activity engaged in by the patient prior to the patient event.
 41. The system of claim 33, wherein, during the on-cycle, the medical device delivers the therapy to the patient according to at least one therapy program that defines a therapy parameter value, and the one or more processors are configured to adjust the therapy by at least modifying the therapy parameter value.
 42. The system of claim 33, wherein, during the on-cycle, the medical device delivers the therapy to the patient according to a first therapy program and the one or more processors are configured to adjust the therapy by at least selecting a second therapy program for the medical device.
 43. A method comprising: receiving, with one or more processors, an indication of an occurrence of a patient event related to a condition of a patient; generating, with the one or more processors, an event marker based on the indication; and adjusting, with the one or more processors, therapy delivered by a medical device to the patient based on the event marker, wherein the medical device delivers therapy to the patient substantially continuously or at regular intervals without relying on feedback from a therapy system.
 44. The method of claim 43, wherein the medical device delivers therapy to the patient according to a therapy parameter value, and wherein adjusting the therapy comprises modifying, with the one or more processors, the therapy parameter value.
 45. The method of claim 43, wherein the medical device delivers therapy to the patient according to a first therapy program, and wherein adjusting the therapy comprises switching, with the one or more processors, from the first therapy program to a second therapy program.
 46. The method of claim 43, wherein the medical device delivers therapy according to a therapy cycle comprising an on-cycle during which therapy is delivered to the patient and an off-cycle during which therapy is not delivered to the patient, and wherein adjusting the therapy comprises: determining, with the one or more processors, whether the medical device is in the off-cycle or the on-cycle of the therapy cycle implemented by the medical device at a time based on the generation of the event marker; with the one or more processors, initiating the on-cycle if the medical device is in the off-cycle at the time, thereby shortening a duration of the off-cycle of the therapy cycle implemented by the medical device at the time; and with the one or more processors, restarting the on-cycle if the medical device is in the on-cycle at the time, thereby elongating a duration of the on-cycle of the therapy cycle implemented by the medical device at the time.
 47. The method of claim 43, further comprising: associating, with the one or more processors, the event marker with a therapy program, wherein the medical device is configured to deliver therapy to the patient according to the therapy program; determining, with the one or more processors, an event metric for the therapy program based on a number of event markers associated with the therapy program; starting a timer; determining, with the one or more processors, a predetermined time period has expired based on the timer; and determining, with the one or more processors, the event metric indicates the therapy program is ineffective for the patient condition after the predetermined time period has expired, wherein adjusting the therapy based on the event marker comprises adjusting a therapy parameter value of the therapy program in response to determining the event metric indicates the therapy program is ineffective for the patient condition.
 48. The method of claim 43, further comprising: receiving, by the one or more processors, event information relating to the patient event, wherein the event information indicates an efficacy of therapy that was delivered to the patient to manage the condition of the patient prior to or during the occurrence of the patient event; receiving, by the one or more processors, additional information relating to the patient event, the additional information comprising at least one of physiological parameter data collected by a sensor prior to or during the occurrence of the patient event, an identification of a type of patient event indicated by the indication, a duration of the patient event, a rating of a severity of the patient event, or an activity engaged in by the patient prior to the occurrence of the patient event; associating the event information and the additional information with the event marker; and storing, by the one or more processors in in a memory of a device, the event information, the additional information, and the associated event marker.
 49. The method of claim 48, further comprising: generating an event score based on the event marker; and comparing the event score to a threshold value, wherein adjusting the therapy delivered by the medical device comprises adjusting at least one therapy parameter value of the therapy when the event score is greater than or equal to the threshold value.
 50. A therapy system comprising: a medical device configured to deliver therapy to a patient substantially continuously or at regular intervals without relying on feedback from the therapy system; and one or more processors configured to receive input indicating an occurrence of a patient event, generate an event marker based on the indication, and adjust the therapy delivered by the medical device to the patient based on the event marker.
 51. The system of claim 50, wherein the medical device is configured to deliver the therapy to the patient according to a therapy parameter value, and wherein the one or more processors are configured to adjust the therapy by at least modifying the therapy parameter value.
 52. The system of claim 50, wherein the medical device deliver is configured to deliver the therapy to the patient according to a first therapy program, and wherein the one or more processors are configured to adjust the therapy by at least switching by from the first therapy program to a second therapy program.
 53. The system of claim 50, wherein the medical device is configured to deliver the therapy according to a therapy cycle comprising an on-cycle during which therapy is delivered to the patient and an off-cycle during which therapy is not delivered to the patient, and wherein the one or more processors are configured to adjust the therapy by at least: determining whether the medical device is in the off-cycle or the on-cycle of the therapy cycle implemented by the medical device at a time based on the generation of the event marker; initiating the on-cycle if the medical device is in the off-cycle at the time, thereby shortening a duration of the off-cycle of the therapy cycle implemented by the medical device at the time; and restarting the on-cycle if the medical device is in the on-cycle at the time, thereby elongating a duration of the on-cycle of the therapy cycle implemented by the medical device at the time.
 54. The system of claim 50, wherein the one or more processors are further configured to: associate the event marker with a therapy program, wherein the medical device is configured to deliver therapy to the patient according to the therapy program, determine an event metric for the therapy program based on a number of event markers associated with the therapy program, start a timer, determine a predetermined time period has expired based on the timer, and determine the event metric indicates the therapy program is ineffective for the patient condition after the predetermined time period has expired, wherein the one or more processors are configured adjust the therapy based on the event marker by at least adjusting a therapy parameter value of the therapy program in response to determining the event metric indicates the therapy program is ineffective for the patient condition.
 55. The system of claim 50, further comprising a memory, wherein the one or more processors are further configured: receive event information relating to the patient event, wherein the event information indicates an efficacy of therapy that was delivered to the patient to manage the condition of the patient prior to or during the occurrence of the patient event, receive additional information relating to the patient event, the additional information comprising at least one of physiological parameter data collected by a sensor prior to or during the occurrence of the patient event, an identification of a type of patient event indicated by the indication, a duration of the patient event, a rating of a severity of the patient event, or an activity engaged in by the patient prior to the occurrence of the patient event, associate the event information and the additional information with the event marker; and store, in in the memory, the event information, the additional information, and the associated event marker.
 56. The system of claim 50, wherein the one or more processors are further configured to generate an event score based on the event marker, compare the event score to a threshold value, and adjust therapy delivered by the medical device to the patient by at least adjusting at least one therapy parameter value of the therapy program when the event score is greater than the threshold value. 